UA128833C2 - Method for manufacturing processed titanium material - Google Patents

Abstract

A method for manufacturing a titanium material in which a titanium ingredient is caused to pass through a gap between a pair of rolls, wherein: at least one roll of the pair of rolls has a plurality of protrusions arranged so as to have a zigzag shape when the surface of the roll is viewed in plan view; the manufacturing method comprises a step in which the protrusions are pressed into the surface of the titanium ingredient, thereby forming a plurality of dimples in the surface of the titanium ingredient; the protrusions are provided with spherical pressing surfaces at the distal ends thereof; and R is within the range from 3 to 30, D is within the range from 2 to 10 and is equal to or less than h, and S is within the range from 2(R2-(R-D)2)1/2 to 3(R2-(R-D)2)1/2, where h (mm) is the height of the pressing surfaces, R (mm) is the radius of curvature of the pressing surfaces of the protrusions, S (mm) is the distance between the centers of adjacent protrusions in the passage direction of the titanium ingredient, and D (mm) is the pressing amount of the protrusions. Using a processed titanium material obtained through this method makes it possible to reduce surface damage produced during hot-rolling.

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION BELONGS

The present invention relates to a method of obtaining a processed titanium product, which can reduce the occurrence of surface defects during hot rolling.

TECHNICAL LEVEL

The usual method of obtaining a titanium product for hot rolling is as follows. First, the ingot is obtained by melting titanium by vacuum arc remelting (VDP, MAK) or electron beam remelting (EPP, EVEK) and hardening. The ingot is then broken by hot deformation, such as rolling in a crimping cage (blooming), forging, or rolling, to form a titanium hot-rolled billet, such as a slab or billet. In addition, a technology has also recently been developed in which the above deformation process can be eliminated by obtaining a rectangular ingot by electron beam remelting, which can be directly subjected to hot rolling.

However, in the massive ingot used in industry, there are large grains up to several tens of mm in the solidification microstructure. If such an ingot is directly subjected to hot rolling without going through a deformation process, inhomogeneous deformation caused by large grains may occur, and sometimes large surface defects may occur. In addition, even in the case where the ingot is passed through a deformation process or the like, if the processing degree is low or the temperature is not suitable for the deformation process, the microstructure of the ingot may be preserved and, conversely, the microstructure may become coarser or similar, and under surface defects may occur during hot rolling.

If surface defects are thereby produced, the yield of a suitable subsequent descaling process will be extremely poor, and for this reason there is a need for a hot-rolled titanium product in which hot-rolled surface defects are prevented.

Patent Document 1 proposes a method in which, when a titanium product ingot is directly hot-treated, deformation is created in the surface layer to grind the grains near the outer layer, and then an area to a depth of 2 mm or more from the surface is subjected to recrystallization by heating to a recrystallization temperature or higher , after which hot processing is performed.

In addition, Patent Documents 2 and C disclose titanium hot-work products in which deformation is created in the near-surface region by plastically deforming the surface of the titanium hot-work product using a steel tool, in which the front end shape has a radius of curvature of from C to 30 mm , or a steel ball with a radius from 3 to 30 mm. Patent Documents 2 and 3 indicate that by performing hot rolling of such hot rolled titanium products, the influence of the rough microstructure of the hardened product can be made negligible, and surface defects can be reduced.

LIST OF PRIOR ART DOCUMENTS

PATENT DOCUMENT

Patent Document 1: UR1-156456А

Patent Document 2: UMO 2010/090352

Patent Document 3: UR2018-1249А

ESSENCE OF THE INVENTION

TECHNICAL PROBLEM

In Patent Document 1, as methods of creating deformation, forging, pressing by rolling and shot blasting are mentioned. However, with conventional shot blasting, since the shot has a small diameter of 0.5 to 1 mm, the amount of deformation created is also small.

In addition, during forging or crimping by rolling, so-called dead metal is formed, which reduces the amount of deformation or causes deformation to occur in a more internal position. Therefore, in some cases, the required thickness of the recrystallized layer may not be provided, or the grinding of the grains may be insufficient.

In Patent Documents 2 and 3, since the deformation is created by striking or pressing a steel tool, in some cases, it takes a long time to ensure a stable deformation on the entire surface, which is not effective. In addition, in the case of high-strength materials, the impact energy may not be transmitted inward, and, therefore, the required thickness of the fine-grained microstructure cannot be provided. Thus, there is still room for further improvement.

The present invention was created taking into account the circumstances described above, and the purpose of the present invention is to create a method of obtaining, with high efficiency, a processed titanium product that can reduce surface defects that occur during hot rolling.

SOLVING THE PROBLEM

The essence of this invention for solving the above-mentioned problem is as follows.

A method of producing a machined titanium product, wherein the titanium feedstock is passed through a gap between a pair of rolls, wherein at least one roll of the pair of rolls has protrusions arranged to be staggered when the roll surface is fully formed and viewed from above , and the method includes the process of forming numerous dimples in the surface of the titanium source material by pressing protrusions into the surface of the titanium source material, in which: the protrusion includes a spherical pressure surface on the front at the end of the protrusion, and when the height of the pressure surface is represented by the value Пп (mm), the radius of curvature of the pressure surface is represented by the value K (mm), the intercenter distance between the protrusions bordering in the direction in which the titanium source material passes is represented by the value 5 (mm), and the amount of indentation by the protrusions is represented by the value O (mm):

K has a value within the range of 3 to 30, p has a value within the range of 2 to 10, and is Пп or less, and

C has a value within the range from 2(82-(8-0)2)!2 to 3(К2-(8-0)2)12,

PRINCIPAL RESULTS OF THE INVENTION

According to the present invention, a method of obtaining a processed titanium product can be created, which allows to reduce the surface defects that occur during hot rolling.

In addition, according to the present invention, even in the case of casting a titanium source material that has not been treated in the deformation process, the surface defects that occur during hot rolling can be stably made into small surface defects, and high-efficiency production of excellent hot-rolled products can be ensured. products and cold-rolled products.

BRIEF DESCRIPTION DRAWING

Figure 1 is a multiview view showing perspective views illustrating examples of the shape of a machined titanium product according to the present invention.

Figure 2 is a schematic cross-sectional view of a processed titanium product according to this embodiment.

Figures C(a), (B) and (c) are views to describe the configurations of placement of wells in this embodiment.

Figure 4 is a schematic cross-sectional view of a processed titanium product according to this embodiment.

Figure 5 is a schematic side view of a processing machine used in a method of obtaining a processed titanium product according to this embodiment.

Figures b), (B) and (c) represent views for describing the configurations of placement of protrusions b (ba, bB, bs) in this embodiment.

Figures 7(a) and 7(5) are enlarged sectional views in the direction of the roll diameter to describe the shapes of the protrusions 6 (ba, ba) in this embodiment.

DESCRIPTION OF OPTIONS FOR IMPLEMENTATION OF THE INVENTION

Embodiments of the present invention are described below with the accompanying drawings.

In order to reduce the surface defects caused by hot rolling, the authors of this invention have conducted thorough research on a method to make harmless the rough microstructure of the solidified ingot, the grain diameters of which can reach several tens of mm, and also the effects of the microstructure of the solidified product that remain even after deformation , and, in addition, relative to the processed titanium product to which the method is applied, and as a result, the authors of this invention obtained the following discovered facts, and thereby came to this invention.

As a method of grinding the coarse microstructure of the hardened product or eliminating the areas where the effects of the microstructure of the hardened product remain, it is considered to create a designated deformation of the surface of the titanium source material, and then perform recrystallization by a predetermined heat treatment, such as heating during hot rolling.

According to the present invention, by rolling the titanium source material using a roll having predetermined protrusions and pressing the protrusions into the titanium source material 60, numerous dimples (roughness) are formed in the surface of the titanium source material and create deformation of the outer layer of the source material. The authors of this invention found that the processed titanium product obtained in this way includes a deformed microstructure in the outer layer, and can significantly suppress surface defects during hot rolling. In addition, in the present invention, by pressing the protrusions with the physical creation of plastic deformation and the formation of dimples, the deformation can be stably carried out, and furthermore, the deformation can be effectively and properly created at the bottom of the dimples, and the occurrence of surface defects can be averted by the formation of a fine recrystallized microstructure in the outer layer when heated during subsequent hot rolling.

Below, the method of obtaining a processed titanium product according to this embodiment is described with reference to the drawings. It should be noted that in all the drawings to which references are given below, the thickness and size ratio of the corresponding constituent elements have been adjusted to simplify the illustration.

First, the machined titanium product formed by the method of obtaining the machined titanium product according to this embodiment (which is also referred to as the "machined titanium product according to this embodiment") will be described first.

A titanium product is a titanium product that includes a deformed microstructure in the outer layer, and which is suitable as a raw material that is then subjected to hot rolling. In addition, in the machined titanium product, the radius A: curvature of the bottom of the dimples is from 3 to 30 mm, and the dimples are arranged to form a checkerboard shape in the top view.

In addition, in the machined titanium product according to this embodiment, when the radius of the corresponding dimples is represented as g: (mm), the center-to-center distance P between the dimples that are adjacent and the distance О between each of the rows in which the dimples are placed is preferably within the range from (2xh) to (3x) mm.

In addition, the titanium raw material used in this method to obtain the processed titanium product according to this embodiment preferably consists of technically pure titanium or a titanium alloy.

In addition, examples of the titanium source material used in the method of obtaining the processed titanium product according to this embodiment include ingot, slab, bloom and billet. As for their shape, the diameter of the titanium source material, the cross-section of which has a circular shape, is from 100 to 300 mm, and preferably from 90 to 250 mm.

As will be described later, the processed titanium product according to this variant of implementation is obtained using a roll with protrusions, and pressing the roll with the formation of pits in the surface of the titanium source material to create deformation in it. The details of the method of obtaining will be described later.

Figure 1 illustrates examples of a processed titanium product according to this embodiment. The processed titanium product according to this embodiment may be a slab 1, as shown in figure 1(a), a bloom 2, as shown in figure 1(b), a ticket (rectangular ticket) 3, in which the cross-section perpendicular to the longitudinal direction is rectangular, as shown in figure 1(c), or a rod (round bar) 4, in which the cross-section perpendicular to the longitudinal direction is circular, as shown in figure 1(4). In addition, numerous pits 16, 25, ZB and 45 are formed in the surface of slab 1, illustrated in figure 1(a), the surface 2a of bloom 2, illustrated in figure 1(5), the surface of rectangular billet 3, illustrated in figure 1 (c), and in the surface 4a of the round rod 4, illustrated in figure 1(4), respectively. It should be noted that, although not shown in the drawings, in the case where the machined titanium product has a rectangular cross-section illustrated in any of the figures from Figure 1(a) to Figure 1(c), pits may also be formed in side surfaces in the longitudinal direction.

Figure 2 is a schematic sectional view taken along the line A-A in the drawings from Figure 1(a) to Figure 1(4). It should be noted that when the corresponding machined titanium product illustrated in the drawings from Figure 1(a) to Figure 1(a) is cut along the line A-A, the cross-sectional configuration will be the same cross-sectional configuration for each of the machined titanium products illustrated in the drawings from Figure 1(a) to Figure 14), and therefore, for convenience of description, the views of the discussed cross section are combined and illustrated in figure 2.

It should be noted that the position at a depth of 1/2 of the thickness, in the case of the slab illustrated in figure 1(a) or the plume illustrated in figure 1(Bb), represents a position at a depth of 1/21 relative to the thickness of the slab or the thickness of bloom, respectively. Furthermore, in a ticket C with a rectangular 60 cross-section having an aspect ratio of about 1, as shown in Figure 1(c),

the position at the depth of 1/2 thickness represents the center of gravity of the cross section of the ticket, and in the rod 4 with a circular cross section illustrated in Figure 1(a), the position at the depth of 1/2 thickness represents the center position of the cross section of the rod.

Grinding of the crystalline microstructure of the processed titanium product is necessary for stable suppression of surface defects that may occur during hot rolling.

Of course, while it is possible to prevent the formation of surface defects by grinding the crystalline microstructure of the entire machined titanium product, in order to do so, it is necessary to create a high degree of deformation in the entire source material. In addition, while there are situations where, if necessary, rolling in the width direction is performed before hot rolling, if the degree of compression in the width direction rolling relative to the casting of the titanium source material is high, in some cases, folds occur due to rough microstructure of the casting, and surface defects are formed after hot rolling.

In order to stably suppress surface defects, which are not only due to the microstructure of the casting, but which are also formed from folds that occur when rolling in the width direction is intensified, it is necessary to provide at least the outer layer with a thin recrystallized microstructure during hot rolling. Here, the term "outer layer" refers to the area from the bottom of the pit to the position at a depth of 3 mm. In addition, the bottom of the fossa is the deepest part of the fossa.

To make the outer layer such that it has a fine recrystallized microstructure during heating during hot rolling, it is necessary to create a deformation to a predetermined extent from the bottom of the pit to a position at a depth of 3 mm. As a result of various studies by the authors of this invention, it was found that if the equivalent deformation in the area from the bottom of the pit to the depth

With mm is 0.2 or more, recrystallization occurs during heating during hot rolling, and a fine microstructure can be formed. The thickness of the recrystallized layer obtained in this way will be 3 mm or more, and surface defects can be removed during hot rolling. A thickness of 3 mm or more is sufficient as the thickness of the recrystallized layer, and although the upper limit is not specifically prescribed, increasing this thickness will require an increase in the pressing load to create deformation. Thus, from the standpoint of limitations relating to the load capacity of the pressing device, the practical upper limit of the thickness of the recrystallized layer is 25 mm.

Thus, since numerous dimples are formed in the surface of the processed titanium product according to this embodiment, the processed titanium product is a processed titanium product for which sufficient deformation has been created in the outer layer of the source material, and during heating during hot rolling, it can be formed a recrystallized layer that is fine-grained and in which the grain diameters are uniform.

Next, a preferred form of pit formed in a processed titanium product according to this embodiment will be described.

As shown in Figures 1(a) to 1(4), multiple dimples Ta to 4a are formed in the surface of the processed titanium product according to this embodiment, and the radius A: of curvature of these dimples is preferably adjusted to a value within the range of 30 mm.

The rationale for giving the bottom of the pit a shape in which the radius B: of curvature is from 3 to 30 mm, that is, spherical, is that when a protrusion having the same radius of curvature is pressed into the titanium source material 1 to form a pit, the formation of an area of dead metal near the bottom of the hole becomes difficult, and the flow of metal to the periphery becomes isotropic (concentric). In other words, the rationale is that forming the bottom of the pit spherically facilitates the introduction of deformation into the periphery of the pit. In addition, as will be described in detail later, by forming the pit using a protrusion having a spherical pressure surface in which the radius K of curvature at the front end is from 3 to 30 mm, that is, a protrusion whose front end is a spherical head, it is difficult to attach pit form in which it becomes steeply concave so that the end of the pit develops into an overlapping surface defect during hot rolling. According to these considerations, the contour of the bottom of the pit is preferably given a shape in which the radius of curvature Ni is a value within the range from 3 to 30 mm (the front end has a spherical shape that corresponds to the spherical shape of the protrusion head).

If the radius Ni of curvature of the spherical shape of the bottom of the pit is less than 3 mm, the bottom of the pit may become steeply concave, which turns into a surface defect, or it may make it impossible to create a deformation sufficient in the direction of the depth in the outer layer of the processed titanium product, and the thickness of the outer layer, in which the microstructure is crushed may be shallow, and thus surface defects may occur. Therefore, the radius B: curvature of the pit bottom is preferably made to be 3 mm or more. 60 On the other hand, if the radius Pi of curvature of the pit exceeds 30 mm, there is a danger that the area of dead metal will be large and it will be impossible to create sufficient deformation in the outer layer of the machined titanium product, and therefore the radius Vi of curvature of the pit is preferably made to be 30 or less. Therefore, when the radius B of curvature of the pit is made to be 30 mm or less, the area of the dead metal will be small, and the deformation can be created concentrated to a sufficient depth in the outer layer of the processed titanium product.

Next, the preferred configuration of placing pits on a processed titanium product according to this embodiment will be described with reference to the drawings, given as an example of a situation where a slab (Figure 1(a)) is used as a type of titanium source material.

Figures 3(a)-(c) are views for describing dimple placement configurations in this embodiment, and are schematic diagrams of dimples 16, 16', and 15" when the titanium product (slab 1) illustrated in Figure 1(a) is machined ), viewed from above.

It should be noted that conventional designations from Х1 to ХЗ3 on figures З(a)-(c) mean the rows in which the pits are located.

In addition, Figure 4 is a sectional view of the dimples for describing the shape of the dimples in this embodiment, and a sectional view taken along line B-B in Figure C(a).

As shown in figure C(a), when slab 1 is viewed from above, the corresponding rows of X1,

X2 and ХZ protrusions, in which the numerous pits 15 are placed in a regular order in one row, distributed in the width direction or in the longitudinal direction of the slab 1, and the numerous pits 165 are alternately placed relative to each other in the width direction or in the longitudinal direction of the slab 1. Others in other words, the pits 15 are arranged so as to be staggered in the top view. The pits 16, located in such a location configuration, are formed by a roll with protrusions having the same location configuration, and by pressing the protrusions into the surface of slab 1, deformation can be effectively created in the rolled surface of slab 1. It should be noted that the direction of placement of rows X1, Х2 and ХЗ of the protrusions can be one of the direction along the width and the longitudinal direction of the slab 1, and can also be a direction that oriented at a certain angle relative to the width direction (or longitudinal direction). Further, while the configuration in which there are three rows of projections is given here for convenience of description, the number of rows can also be appropriately determined depending on the dimensions (diameter and width, or the like) of the slab 1, the dimensions of the projection roll, which is used when forming dimples, or the size of protrusions, or the like.

In addition, the pits may be placed spaced apart from each other by a certain distance, as shown in Figure C(a) and Figure 4, or, as shown in Figure C(B), the pits may be placed so that, in the while the neighboring pits 1B', which are in the same row, are distant from each other, the corresponding rows, placed across the width or in the longitudinal direction of the slab, are in contact with each other. In addition, as shown in figure C(c), the pits can be placed so that all the pits 1p" are in contact with each other without any gaps between them.

Next, the intercenter distance P between adjacent wells among numerous wells placed in the same row, and the distance O between each of the rows (the distance between rows of wells) will be described.

The term "center-to-center distance P" means, as shown in Figures 3(a)-(c) and Figure 4, that when pits 16, 16, and 16" are viewed from above, the distance between the centers of pits that are adjacent in the same row (for example, in row X1 or in row X2), and the term "distance О between rows of dimples" refers to the distance between the central axes of adjacent rows of dimples (for example, next to X1 and next to X2).

In this embodiment, when the dimple radius is represented as gi (mm), both the intercenter distance P (mm) and the distance between OO (mm) between rows of dimples in both cases are preferably adjusted by (2 xh) or more, and ( Хх) or less.

If the center distance P and the distance O between the rows of dimples are smaller (by 2xhi), the flow of metal may be suppressed, and the amount of deformation created in the periphery of the dimples may be insufficient. On the other hand, if the intercenter distance Р and the distance ОО between the rows of dimples are greater (in terms of Х), then since the gap between adjacent dimples will be excessively widened, in some cases the magnitude of the created deformation will be insufficient, and as a result, surface defects after hot rolling will not will be sufficiently diverted.

Although the preferred shape of dimples according to this embodiment has been described above with the example of slab 1 illustrated in Figure 1(a), dimples with the same shape as described above are also formed in bloom 2 illustrated in Figure 1(5), a rectangular billet 3, illustrated in figure 1(c), and in round bar 4, illustrated in figure 14). 60 The titanium source material in this embodiment is a titanium casting,

used for hot rolling, and examples of titanium source material that may be mentioned include ingot, slab, bloom and billet as described in sections (A) or (B) below. That is, titanium raw material does not include titanium sheet already rolled to a thickness less than a predetermined thickness, by hot rolling or cold rolling. Thus, in the case of a rectangular parallelepiped or cubic-shaped titanium source material, a titanium source material having a thickness of, for example, 100 mm or more is the object of this embodiment, and in the case of a cylindrical titanium source material, the object of this embodiment the implementation is a titanium source material having a diameter of, for example, 90 mm or more. The titanium source material (B) is composed of the microstructure of the hardened product obtained by melting and casting of titanium, and has the microstructure of a casting in which there are coarse grains having a grain diameter of 10 or more. (A) Titanium raw material obtained in the form of a slab or billet, or the like, by creating an ingot by temporary melting of titanium by the methods of vacuum arc remelting (VDP, MAK), electron beam remelting (EPP, EVK) or plasma arc remelting (PDP, RAM), or similar, and then hardening of titanium, and additionally deformation of the ingot with execution hot working, such as rolling in a crimping cage, forging or rolling. (B) A titanium source material obtained by a method in which the deformation process in the above-mentioned approach (A) is eliminated, and in which, when the titanium solidifies after the titanium has been temporarily melted by electron beam remelting or plasma arc remelting, the titanium is formed into a rectangular ingot having a size which can then be directly hot-rolled.

In electron beam remelting, the electron beam irradiation can be condensed by beam polarization, and therefore heat can be easily applied even to the narrow area between the casting mold and the molten titanium, thereby providing good control of the casting surface. In addition, there is a high degree of freedom relative to the cross-sectional shape of the casting mold. Therefore, a rectangular or cylindrical ingot of a size that can be directly subjected to hot rolling, as described in the above section (B), is preferably melted using an electron beam melting furnace. In addition, in plasma-arc remelting, although the principle of heating is different from the principle of heating in electron beam remelting, the same effect as the effect of electron beam remelting is obtained.

Titanium raw material mainly consists of technically pure titanium or titanium alloy.

The term "technically pure titanium" includes technically pure titanium, as defined for categories from Class 1 to Class 4 according to the LZ H4b00 standard, and the corresponding technically pure titanium, which is specified by Marks 1 to 4 according to the AZTM 265B standard, and

Mark I (M/G. 3.7025), Mark II (M/. 3.7035) and Mark PI (M/. 3.7055) in accordance with the IM 17850 standard. That is, technically pure titanium, which is the purpose of this invention, consists of, in mass . 95, with C: 0.1 5 or less, H: 0.015 95 or less, 0: 0.4 95 or less, M: 0.07 uy or less, and Re: 0.5 U5 or less, with the rest of Those. Further, "Y" in relation to the content of each element means "percentage by mass".

On the other hand, relatively low-alloy titanium alloys or a-type titanium alloys, they are suitable for the use of an alloy acceptable for the required application option.

More preferred is a low-alloy alloy in which the alloying component is substantially less than 595 or less. For example, an alloy with high corrosion resistance to which Ra «0.15 95, Ni «0.10 95, and a rare earth metal «0.02 95 were added, or a heat-resistant alloy to which Si were added, can be mentioned as examples. AI, bi, Zp, MB, and Re, in a quantity that is less than 5 95 in total.

More specifically, as low-alloyed alloys, for example, alloys with high corrosion resistance (A5TM-Grades 7, 11, 16, 26, 13, 30 and 33, or LI15-classes, which correspond to A5TM-Grades, or alloys obtained by additional addition to of various elements in small quantities), available Ti-0.5Sy, Ti-1.0Sy, Ti-1.00y-0.5M, Ti-1.0by-1.051p-0.351-0.25M6, Ti-0.5A1I-0.4551, Ti-0.9A1- 0.355i and the like. In addition, as titanium alloys of the c-type, for example, there are Ti-5AI-2.551, Ti-6AI-25p-471-2Mo, Ti-6AI-2.7551-421-0.4АМо-0.4551 and the like.

As titanium alloys of the a--D type, for example, known Ti-6AI-4M, Ti-6AI-6M-251, Ti-6AI-7M, TI-ZAI-2.5U,

TI-ZAI-BM, TI-BAI-251p-221-4Mo-4St, Ti-6AI-251-421-6Mo, Ti-1Re-0.35Pro, Ti-1.5Re-0.5Pro, Ti-5BA! - 1Tge, Ti-BAI-1Re-0.351i, Ti-BAI-2Ee, Ti-BAI-2Re-0.35i, Ti-BAI-2Re-ZMo, and Ti-4.5AI-2Be-2U-3Mo and therefore similar.

In addition, p-type titanium alloys are known, for example, Ti-11.5Mo-621-4.551, Ti-VM-ZAI-6St-4Mo-47t, Ti-10m-2Ee-ZMo, Ti-13M-11С1-ZAI , Ti-15M-ZAI-Z3SI-35p, Ti-6.8mMo0-4.5Ee-1.5AI, Ti-20M-4AI-1501, Ti-22U-4AI and the like.

The titanium alloy according to the present invention can provide the target function of the surface of the processed titanium product when it contains, for example, more than 0 95 elements of one or more types selected from the group consisting of: O: vido to 0.5 95, M: fromO to 0 ,2 95, C: from 0 to 2.0 905, AI: from O to 8.0 95, op: from O to 10.0 905, 2g: from O to 20.0 96, Mo: from 0 to 25.0 95, Ta: from 0 to 5.095, M: from O to 30.0 95, MB: from O to 40.0 95, 5i: from O to 2.0 95, Ge: from O to 5.0 95, St: from O to 10.0 95, C: from O to 3.0 95, Co: from O to 3.0 9o, Mi: from 0 to 2.0 95, elements of the platinum group: from

O to 0.5 95, rare earth metals: from O to 0.5 95, B: from O to 5.0 95, and Mn: from O to 10.0 95.

Elements that can be contained in titanium other than the above elements are elements that are expected to increase strength or the like by solid solution hardening or dispersion hardening (there are cases where the elements are not dissolved and cases where elements cause the formation of separated phases) which are known as common knowledge relative to metallic materials. The elements, in terms of atomic number, from hydrogen (1) to astatine (85) (but excluding the elements of the noble gases, which make up

A group of 18 elements) are given as examples of these elements, and the content of these elements is assumed to be approximately 5 95 in total.

The rest, other than the above-mentioned elements, are Ti and impurities. Impurities can be contained in a range that does not impair the target characteristics, and other impurities are impurity elements that were mainly introduced from the raw material or from scrap, and elements that were mixed during manufacturing, with C, M, O, He . elements such as 5i, A! and 5, which are mixed during receipt. It is believed that the range in which these elements do not impair the target characteristics of the present application is about 2 95 or less.

In addition, the titanium alloy according to the present invention may contain, for example, elements of one or more types selected from the group consisting of: O: from 0.01 to 0.5 95, M: from 0.01 to 0.2 90, C: from 0.01 to 2.0 95, AI: from 0.1 to 8.0 95, 5p: from 0.1 to 10.0 95, 2g: from 0.5 to 20.0 95, Mo: from 0.1 to 25.0 95, Ta: from 01 to 5.0 95, M: from 1.0 to 30.0 U, MB: from 0.1 to 40.0 95, 5i: fromO/1 to 2.0 uy, Be: from 0.01 to 5.0 95, Сg: from 0.1 to 10.0 95, Сy: from 0.3 to 3.0 95, Со: from 0.05 to 3.0 9o, Mi: from 0.05 to 2.0 956, elements of the platinum group: from 0.01 to 0.5 95, rare earth metals: from 0.001 to 0.5 95, A: from 0.01 to 5.0 95, and MP: from 0.1 to 10.0 9.

The titanium alloy according to the present invention more preferably contains elements of one or more types selected from the group consisting of: O: from 0О.02 to 0.4 95, M: from 0О.01 to 0.15 95, C: from 0, 01 to 1.0 5, A: from 0О.2 to 6.0 95, Zp: from 0.15 to 5.0 95, g: from 0.5 to 10.0 U, Mo: from 0.2 to 20.0 95, Ta: from 0.1 to 3.0 95, M: from 2.0 to 25.0 95, MB: from 0, 15 to 5.0 905, with: from 0.1 to 1.0 95, Ev: from 0.05 to 2.0 95, Sg: from 0.2 to 5.0 95, C: from 0.3 to 2.0 95, Co: from 0.05 to 2.0 95, Mi: from 0.1 to 1.0 96, elements of the platinum group: from 0.02 to 0.4 95, rare earth metals: from 0.001 to 0.3 96, B: from 0.1 to 5.0 95, and Mn: from 0.2 to 8.0 95, and even more preferably contains elements of one or more types selected from the group consisting of: O: fromO,OZ to 0.3 90, M: from 0, 01 to 0.1 95,

C: from 0.01 to 0.5 95, AI: from 0.4 to 5.0 95, Zp: from 0.2 to 3.0 95, 4g: from 0.5 to 5.0 U, Mo: from 0.5 to 15.0 6, Ta: from 0.2 to 2.0 95, M: from 5.0 to 20.0 95, MB: from 0.2 to 2.0 95, bi: from 0.15 to 0.8 95, Ev: from 01 to 1.095, St: from 0.2 to 3.0 965, C: from 0.3 to 1.5 965, Co: from 0.1 to 1.0 95, Mi: from 01 to 0.8 96, platinum elements groups: from 0.03 to 0.2 95, rare earth metals: from 0.001 to 0.1 95, B: from 0.2 to 3.0 95, and Mn: from 0.2 to 5.0 95.

Here, more specifically, Ky, Ky, Ra, O5, Ig, and RI are mentioned as elements of the platinum group, and may contain elements of one or more of these elements. In the event that the titanium alloy contains elements of the platinum group of two or more types, the content of the elements of the platinum group described above refers to the number of elements of the platinum group. In addition, as rare earth metals (REMs), more specifically, the mentioned Zs, U, Ha, Se, Rg, Ma, Pt, 5t, Em, sa,

Т, бу, Но, Ег, Тт, МБ и и, and these elements may contain elements of one or many types. In the case where the titanium alloy contains rare earth metals of two or more types, for example, a mixture or combination of rare earth metals such as mixed metal (Mt) or didymium alloy can be used. In addition, in the event that the titanium alloy contains rare earth metals of two or more types, the content of the above described rare earth metals means the amount of rare earth metals.

Next, the method of obtaining a processed titanium product according to this embodiment is described. 60 The method of obtaining a processed titanium product according to this embodiment is a method of obtaining a processed titanium product by passing the titanium source material through the gap between a pair of rolls with the formation of numerous dimples in the surface of the titanium source material. In the method of obtaining a processed titanium product according to this embodiment, a roll having multiple projections staggered when the surface is fully formed and visible from a top view is used as at least one roll from a pair of rolls. By using such a roll, which has numerous protrusions on the surface, and pressing the protrusions into the surface of the titanium source material, dimples are formed and deformation is created in the near-surface area of the source material. Generally, when trying to create deformation in an ingot or the like by forging or using a large diameter roll, metal flow does not occur in the area that is in contact with the mold, and an area known as "dead metal" is formed. Since the amount of deformation in the dead metal is small, when the deformation is created by forging or using a large diameter roll, the deformation is not created in the near-surface region, but instead is created in the region further inward from the near-surface region, and the microstructure of the near-surface region cannot to be made of a fine-grained microstructure.

Therefore, the authors of the present invention conducted research on a method that prevents the occurrence of dead metal and also does not create coarse-grained areas by uniformly distributing the strain in the outer layer of the titanium source material in an effective manner, and found that if the titanium source material is processed in the following manner, it is possible effectively create deformation in the outer layer.

The method of obtaining a processed titanium product according to this embodiment is described in detail below.

In the method of obtaining a processed titanium product according to this embodiment, the protrusions have a spherical pressure surface at their front end, and when the height of the pressure surface is represented by the value Пп (mm), the radius of curvature of the pressure surface is represented by the value K (mm), the center distance between the protrusions, which bounded in the direction in which the titanium source material is passed, represented by the value 5 (mm), and the amount of indentation by the protrusions is represented by the value О (mm), the method is performed under conditions that

K has a value in the range of 3 to 30, O has a value in the range of 2 to 10, and is Pn or less, and 5 has a value in the range of 2(82-(8-0)2)!?2 to Z3(82-(8-0)2)12.

In the method of obtaining a processed titanium product according to this embodiment, the distance Y. between each row in which the protrusions are placed is preferably in the range from 2(82-(8-0)2)12 to 3(К2-(8-0)2)172,

In addition, in the method of obtaining a processed titanium product according to this embodiment, the pit formation process is preferably performed in a state in which the temperature of the surface of the titanium source material is a temperature that is 0 "C or more and 500 "C or lower.

In addition, in the method of obtaining a processed titanium product according to this embodiment, the titanium source material before the dimple formation process is preferably a titanium source material obtained using electron beam remelting or plasma arc remelting.

In addition, in the method of obtaining a processed titanium product according to this embodiment, the titanium source material preferably consists of technically pure titanium or a titanium alloy.

In addition, in the method of obtaining a processed titanium product according to this embodiment, the titanium source material is preferably a slab, bloom or billet.

As a processing machine that is used in the method of obtaining a processed titanium product according to this embodiment, a two-roll type processing machine including a pair of rolls 2 will be described as an example, and a schematic side view of the two-roll type processing machine is illustrated in Figure 5. It should be noted that in the following description, as an example, a situation will be described where a slab (Figure 1(a)) is used as a type of titanium source material, which is processed object. In addition, the wide arrow in the drawing shows the direction of stretching of the titanium source material (slab) 1, and each thin arrow means the direction of rotation of the corresponding roll 2.

As shown in Figure 5, this variant of implementation represents the method by which the titanium source material (slab) 1 is processed, while at the same time passing the titanium source material 1 between a pair of rolls by. More specifically, this version of the implementation represents a method in which, when extending the titanium source material 1 between a pair of rolls za, on which 60 numerous protrusions b are placed, having the shape of the front end with a radius K of curvature from З to 30 mm,

press the projections b into the surface Ta for the plastic deformation of the surface Ta to a predetermined value and the formation of dimples 16 in the surface a, and thereby create a deformation of the outer layer of the titanium source material 1. It should be noted that on the entire titanium source material it is enough for the dimples 16 to be are formed and deformation has been created, at least in the surface that will be the rolled surface during hot rolling in the subsequent process. In other words, the surface in which the pits 16 are formed may be the surface of only one part of the source material, or may be the entire surface of the source material. Thus, it is sufficient that the protrusions b, as described above, were formed on at least one roll from a pair of rolls 5a.

According to this production method, a machined titanium product that can significantly suppress surface defects during hot rolling can be produced easily and with high productivity.

It should be noted that in this embodiment, when the titanium source material 1 is drawn between the rolls having protrusions 6 on their surfaces, thereby forming pits 15 in the surface of the titanium source material 1, the number of cycles of drawing the titanium source material 1 (the number of times for which the titanium source material 1 passes between the rolls) can be single, or can be set as two or more times. In other words, similar to the reverse rolling situation, after the titanium raw material 1 has been drawn between the rolls ba, pits have been formed in its surface once, the direction of drawing for the second time can be set to the opposite direction of drawing relative to the first time, and the titanium raw material 1 can then be passed between the rolls again to press the protrusions 6 into its surface. In addition, this method of pressing is not specifically limited, and the number of times of performing the pressing process can be determined within the range in which cracking of the titanium source material does not occur.

In addition, the shape of the titanium source material, which is the processed object according to this embodiment, may be the shape of the slab illustrated in Figure 1(a) or the bloom illustrated in Figure 1(B), or may be the shape of a ticket 3, in which the cross-section perpendicular to the longitudinal direction is rectangular, as shown in figure 1:(c), or rod 4, in which the same cross-section is circular, as shown in figure 1 (a).

In the event that the titanium source material is a slab or bloom, since the surface having the largest area in the titanium source material will be the rolled surface during hot rolling, it is sufficient to form dimples on at least this surface. In addition, in the case where the titanium source material is a ticket, the entire surface that extends in the longitudinal direction can be a rolled surface.

Therefore, for example, in the case of a ticket with a rectangular cross-section, it is desirable to form dimples over its entire surface, and to create deformation in the entire surface of the titanium source material. For example, when a rod 4 having a circular cross-section as shown in Figure 1(4) is used as a titanium source material, it is desirable to perform the processing using drum-type or conical-type rolls in which a plurality of predetermined protrusions are provided, as in the case of Mannesmann rolling process. More specifically, for example, it is desirable to form dimples and create deformation in the surface of the workpiece by a method in which multiple drum-type (or conical-type) rolls (for example, three rolls) are placed in the circumferential direction of the round bar 4, and the round bar 4 is rolled and drawn in the direction movement with simultaneous rotation.

Although this embodiment has been described above with the provision of a two-roll type machining machine as shown in Figure 5 as an example, any type of machining machine can be used in the method of obtaining a machined titanium product according to the present invention, and the Mannesmann rolling process can be used. as described above, or the like, and the number of rolls may also be three or more. Even in this case, it is enough that the protrusions 6 according to this embodiment were formed on at least one roll.

As shown in figure 5, on the surface of the rolls, numerous protrusions 6 are formed, having the shape of the front end with a radius K of curvature from З to 30 mm. In addition, the multiple protrusions 6 on each roll 5a are arranged so as to be staggered in the case where the surface of the roll 5a is fully formed and viewed from above.

The rationale for giving the pressure surface of the front end of the projection Э of a spherical shape, in which the radius K of curvature is from 3 to 30 mm, i.e., a spherical head, is that when the protrusion Э is pressed into the titanium source material 1, and the pit 16 is formed, it becomes difficult 60 the formation of an area of dead metal near the bottom of the pit 16, and the flow of metal to the periphery becomes isotropic (concentric). In other words, the rationale is that forming the front end of the protrusion b in the form of a spherical head facilitates the introduction of deformation into the periphery of the pit 16 formed after the depression of the protrusion 6. In addition, the rationale is also that by providing the front end of the protrusion b, which is depressed , the shape of a spherical head, the formation of a pit 16 with a steeply concave shape, in which the end of the pit develops into an overlapping surface defect during hot rolling. For example, if the shape of the front end of the protrusion is made rectangular, in the form of a rectangular pyramid or a triangular pyramid, there will be a need for a flat section and angled corner sections in the protrusion. When pits are formed using protrusions of this type, in some cases there will be areas of dead metal on the flat areas. In addition, the metal flow can be restricted at the corners among the angular areas of the dimples, and this can make it difficult to create a deformation in the direction of the depth of the source material. Therefore, the pressure surface at the front end of the protrusions b, created on the roll 5a, is made with a spherical shape (spherical head), which has a radius K of curvature from З to 30 mm.

If the radius K of curvature of the spherical pressure surface (spherical head) at the front end of the protrusion b is less than 3 mm, when the amount of compression of the protrusion b is large (for example, 2 mm or more), the protrusion b may form a steep concavity, which turns into a surface defect , while, on the other hand, if the amount of Ю of protrusion compression is made small (for example, less than 2 mm), then steep concavity does not occur, the deformation will not be in sufficient measure is created in the direction of depth in the outer layer of the source material, and the thickness of the outer layer in which the microstructure grinding takes place will be small, and surface defects will occur. Therefore, the radius K of curvature is made to be 3 mm or more.

On the other hand, if the radius K of curvature is greater than 30 mm, the area of dead metal will be large, and it will be impossible to create sufficient deformation in the outer layer of the source material. Therefore, the radius K of curvature is made to be 30 mm or less, and thus the area of the dead metal will be small, and the deformation can be created concentrated to a sufficient depth in the outer layer of the source material. It should be noted that if the radius K of curvature is small, it will be easily affected by the wear of the projection 6, and therefore the lower limit of the radius K of curvature is preferably 5 mm. In addition, if the radius K of curvature is large, the load applied to the roll increases, and therefore the upper limit of the radius K of curvature is preferably 15 mm.

In this embodiment, rolls ba, including projections b, which have the shape as described above, are used to create deformation in the titanium source material 1, with the formation of dimples 15 as a result of pressing the projections b into the titanium source material 1, and the value О of the compression in this time is from 2 to 20 mm, and made no greater than the height Пп (mm) of the pressure surface of the protrusion.

In order to sufficiently suppress the formation of surface defects after hot rolling, it is effective to grind the outer layer to a depth of 3 mm or more from the surface of the treated titanium product before hot rolling. In this embodiment, in order to grind the outer layer to a depth of 3 mm or more from the surface of the titanium source material, it is necessary to create a deformation formed at the amount of compression to a depth of 2 mm or more from the surface of the source material. In other words, the depth of the concave portion of the pit 16 formed by pressing the protrusion b is made to be 2 mm or more. On the other hand, if the value Y of the indentation is greater than the height n of the pressure surface of the projection 6, in some cases a steep concavity may occur, which turns into a surface defect, and metal flow will not occur. Therefore, the value Y of the depression formed by the protrusion 6 is regulated within the range from 2 to 10 mm, and is made no greater than the height Y of the pressure surface of the protrusion.

In order to create sufficient deformation in the outer layer of the source material so that the microstructure of the outer layer is crushed after hot rolling, the protrusions 6 are pressed with an indentation value О of 2 mm or more, and in order to obtain an indentation value О, it is desirable to make the height H of the protrusion 6 greater than the target value About squeezing. If the height H of the protrusion 6 is very small, it may become impossible to ensure a sufficient amount of compression ХО. For these reasons, the height H of the protrusion 6 can be made higher than the height n of the pressure surface of the protrusion E (see Figure 7(B) described later). In addition, the spherical pressure surface formed at the front end of the projection b can be a shape having such a ratio that "the height Пп of the pressure surface-radius of curvature К", i.e., a hemispherical shape having such a ratio that "the height п pressure surface of "radius K of curvature". 60 It should be noted that the term "spherical" implies a shape that is part of a spherical surface, and can, for example, be a hemispherical shape, as shown as an example in Figures 7 a) and (B).

Next, the configuration of placing the protrusions 6 on the roll 5a will be described.

Figures b(a)-(c) are views for describing the placement configurations of the protrusions 6 (ba, 665, bs) in this embodiment, and are schematic representations of the protrusions ba, 6B and bs when the roll surface 5a is fully formed, and it is viewed from above. It should be noted that the notations from U1 to UZ on figures b(a)-(c) in each case mean a number of protrusions.

In addition, Figure 7(a) and Figure 7(5) are enlarged sectional views in the direction of the roll diameter to describe the shape of the protrusions 6 (ba, ba) in this embodiment, and in particular,

Figure 7(a) is a sectional view taken along the C-C line in figure b).

As shown in figures b(a)-(c), when the surface of the roll ba is fully formed and it is viewed from above, the corresponding rows of U1, 2 and UZ protrusions, in which numerous protrusions 6 (ba, 6B, bs) are placed in a regular order in one row, distributed in the width direction or in the rim direction of the roll 5a, and numerous protrusions 6 (ba, bB, bs) alternately placed one relative one in the width direction or the rim direction of the roll. In other words, the protrusions 6 are placed so as to be staggered in the top view. Pressing the protrusions b formed in such a placement configuration into the surface Ta of the starting material 1 with the formation of dimples 15 can effectively create a uniform deformation in the rolled surface of the starting material 1. It should be noted that the direction of placement of rows ХУ1, 2 and УЗ of the protrusions can be along one of the rim direction and the direction along the width of the roll 5a, and can also be a direction that is oriented at a certain angle relative to rim direction (or width direction). Further, while the configuration in which there are three rows of protrusions is given here for convenience of description, the number of rows may also be appropriately determined depending on the dimensions (diameter and width, or the like) of the roll used, or the dimensions of the protrusions 6, or the like.

In addition, the protrusions E can be arranged to be spaced apart from each other by a certain distance, as shown in Figure b(a) and Figure 7(a), or, as shown in Figure (B), the protrusions can be arranged so that , while the adjacent protrusions 65 are distant from each other, the corresponding rows placed in the rim direction or the roll width direction are in contact with each other. In addition, as shown in figure b(c), the protrusions can be placed so that all the protrusions bs are in contact with each other without any gaps between them.

It should be noted that although Figure 7(b) also illustrates an example in which, similar to Figure 7(a), the protrusions are spaced apart without the protrusions contacting each other as described above, the shape of the protrusion b can be with a height H that is greater than the radius K of the curvature of the protrusion ba. In this case, the height H of the protrusion has an area that is greater than the radius

EC of curvature, i.e., a section (columnar section) p perpendicular to the roll surface.

Next, the intercenter distance 5 between adjacent protrusions b among numerous protrusions 6 placed in the same row, and the distance Y will be described. between each of the rows (the distance between rows of protrusions is 6). The term "center-to-center distance 5" means, as shown in Figures b(a)-(c), Figure 7(a) and Figure 7(B), when the protrusions 6 are viewed from above, the distance between the centers of the protrusions b, which are adjacent in the same row (for example, in row U1 or in row U2), and the term "distance I. between rows of projections" refers to the distance between the central axes of adjacent rows of projections (for example, U1 and U2). In addition, the distance Y between rows of protrusions is the distance along the direction of roll rotation.

In this embodiment, the protrusions would be placed so that the center-to-center distance 5 is within the range from 2(Н82-(8-0)2)2 to 3(Н82-(8-0)2)12 (В: radius of curvature, 0 : amount of indentation). In other words, when the radius in the case where the protrusions 6 are viewed from above is taken as "r", the center distance 5 is preferably

BO is within the range of 2g or more and Zgabo is less.

If the intercenter distance Z is less than 2(82-(8-0)2)!? (if less than 2g), there is a possibility that it will be impossible to sufficiently ensure the value О of pressing the protrusions b, and, therefore, the degree of deformation will be insufficient. In addition, if the center-to-center distance 5 is less than 2(82-(8-0)2)!2 (if less than 2g), there is a possibility that when the protrusions 6 are pressed, the surrounding pits will impede the metal flow, and the space for metal flow will be limited and it will be impossible to create sufficient deformation. On the other hand, if the intercenter distance 5 exceeds 3(Н2-(8-0)2)12 (if more than Зg), then, since the gap between adjacent protrusions Э will be excessively widened, in some cases the magnitude of the deformation created by the protrusions in the surface of the titanium of the starting material by the action of protrusions b will be insufficient, and as a result, surface defects after hot rolling will not be sufficiently removed.

It should be noted that even when the center-to-center distance 5 is 2g or more, that is, even when there is a certain amount of gap between the adjacent protrusions b, since the part extruded by the protrusions b is accompanied by the flow of metal to the periphery, in addition to the periphery of the near-surface portion of the pit 16 , which is formed, the deformation can be effectively created also in the corresponding area of the gap.

In addition, in this embodiment, the distance Y between rows of protrusions is preferably adjusted within the range from 2(82-(8-0)2)12 to 3(2E2-(8-0)2)!2. In other words, when the radius in the case where the protrusions 6 are viewed from above is taken as "g", then the distance I between the rows of protrusions is preferably within the range of 2g or more and Zgabo is less.

If the distance GI. between rows of protrusions is less than 2(Н82-(8-0)2)!2 (if less than 21g), although it will be possible to create a certain amount of deformation in some cases, the amount of deformation will be insufficient, and will also pose the problem of increasing the workload and weight swath Therefore, the distance I. between rows of protrusions is preferably adjusted by 2(Н82-(8-0)2)2 or more: On the other hand, if the distance I. between the rows of protrusions is more than 3(82-(8-0)2)12 (if it is more than Зg), since the interval between adjacent rows of protrusions will be excessively widened, in some cases the amount of deformation created by pressing into the surface of the titanium source material of the protrusions b, will be insufficient, and as a result surface defects after hot rolling will not be sufficiently removed. Therefore, the distance is HER. between the rows of protrusions is preferably set to З(Н2-(8-0)2)!? or less

In this embodiment, the rolls 5a, which have the above-described projections 6, are used to perform processing in which pits 16 are formed in the starting material 1 in such a way that the above-mentioned value О of compression can be provided.

While the processing using the roll 5a can be carried out in one pass as long as the above-mentioned compression value O can be ensured, the processing can also be carried out in multiple passes when the performance and specifications of the processing machine are taken into account, and it is enough to be able to the total amount of compression Y is provided, which is within the above-mentioned range.

It should be noted that in this embodiment, as a method of processing the raw material 1, compared to a method that performs compression, such as in the case of forging, the flow of metal is facilitated more by using a rolling method as shown in Figure 5, and this method has the following effect, which becomes difficult to form the above dead metal.

In addition, if a roll ba is used, which covers the entire width of the starting material 1, deformation can be effectively created. In addition, in this embodiment, since only the areas in contact with the protrusions 6 are pressed, the necessary deformation can be created with a lower load than if the titanium source material is pressed across the entire width using a flat roll or punch without protrusions.

When forming multiple dimples in the surface of the titanium source material using a roll b with projections b, the method can be performed on the titanium source material in a cold state without heating the titanium source material, or can be carried out after the titanium source material is heated to a maximum temperature of 500 "C or less.

In this embodiment, a configuration is provided in which the deformation is created on the surface, which will be the rolled surface of the processed titanium product in the cold or warm state. To reduce the appearance of surface defects during hot rolling, it is necessary to ensure the formation of a recrystallized microstructure to a certain depth.

In particular, in the case of high-hardness titanium source material, it is difficult to bring the deformation so far inside the titanium source material, and in order to create the deformation at a position at a depth as far as possible from the outer layer, it is necessary to perform uneven forming processing with a large load. However, it was recently found that as a result of the creation of deformation, plasticity decreases near the outer layer, and cracks form in the surface. Therefore, in order to stably create deformation in the farthest possible position, as well as to improve the plasticity of the outer layer, it is also effective to increase the temperature to a certain extent to reduce the strength of the titanium source material itself. On the other hand, in the case of titanium source material, the strength of which is not so high, it is better to create the deformation at room temperature, because the microstructure of the outer layer can be made fine by creating the deformation concentrated in the outer layer.

On the other hand, if the pitting treatment is carried out at a high temperature of 60 over 500 "C, in some cases the deformation created by the treatment may disappear immediately, and it may be impossible to recrystallize the microstructure during further heating. In addition, at a temperature of more than 500 "C in some cases, an oxidized hardened layer may form on the surface of the titanium source material, and the oxidized hardened layer may be pressed during processing, and during subsequent hot rolling may create surface defects. Since the above problems will not occur if the temperature is 500 "C or less, it is preferable to set it at 500 "C or less as an upper limit.

In addition, since the temperature ranges in which the strength and ductility of the titanium source material increase differ depending on the type of alloy, it is not always favorable that it is good to carry out processing at a higher temperature. For example, in the case of technically pure titanium or the like, although strain twinning, which is one of the most important deformation mechanisms in titanium, is most active near room temperature, strain twinning does not occur at temperatures from about 400 to 500 °C, and hence ductility decreases to a greater extent compared to plasticity at room temperature, and, on the contrary, the formation of cracks becomes easier. On the other hand, in alloy systems containing a large amount of AI, strain twinning hardly occurs even near room temperature, and thus ductility can be ensured by heating to 500 °C or less. In addition, the p-type titanium alloy has the following characteristic , which, being heated for a long time at a temperature from 300 to 500 2С, the strength of the titanium alloy

B-type increases due to dispersion hardening during aging, and plasticity decreases.

In addition, if the titanium source material is heated to a high temperature and the strength of the material is extremely weakened, the ups and downs (in depth) in the surface dimple shapes can become very large when plastic deformation occurs, and surface defects can occur that are caused by the ups and downs. recessions Therefore, it is enough to choose the temperature range according to the grade or brand of the titanium source material so that cracks do not form on the surface after rolling, and the proper recrystallized microstructure and surface condition are obtained.

As described above, in the production method according to this embodiment, while the titanium raw material is drawn between a pair of rolls on which numerous protrusions are placed, the protrusions are pressed into the surface of the titanium raw material with plastic deformation of the surface to a predetermined extent, and pits are formed in the surface As a result, deformation can be stably and efficiently created in the outer layer of the source material. In addition, by ensuring the formation of a fine recrystallized microstructure in the outer layer by heating during subsequent hot rolling, the occurrence of surface defects can be suppressed.

In addition, surface defects after hot rolling are significantly prevented by the processed titanium product formed by the production method according to this embodiment. By applying the present invention to a rectangular or cylindrical ingot, the effect of being able to suppress surface defects to a non-problematic level when hot-rolled to form a sheet, coiled strip, or rod, even without being subjected to a deformation process such as blooming, can be demonstrated.

The heating temperature, when the processed titanium product according to this embodiment is subjected to hot rolling, is preferably adjusted to a value within the range from 800 C to 950 C in order to reduce the resistance to deformation. In addition, to suppress scale formation that occurs during slab heating, it is desirable that the heating temperature be lower than the pD conversion point. Here, "B-transformation point" refers to the lower temperature limit at which the titanium parent material becomes B-single-phase upon heating.

Thus, the processed titanium product obtained according to this embodiment exhibits effects not only that it can be favorably hot-rolled, but also that surface defects are markedly suppressed in the hot-rolled material obtained by hot-rolling, thereby ensuring the possibility of obtaining a clean product even when it is subsequently subjected to cold rolling.

In addition, according to this embodiment, even in the case of casting titanium source material relative to the fact that the ingot has not been subjected to deformation processing, the surface defects that occur during hot rolling can be made insignificant, and excellent hot-rolled products can be obtained. products and cold-rolled products.

In addition, when this embodiment is applied to a titanium source material that has been subjected to processing in the deformation process, the surface defects that occur during hot rolling will be extremely small. As a result, it is possible to additionally increase the yield of suitable scale removal from hot-rolled sheet or rod, as well as the yield of the final product.

EXAMPLES

The present invention is described below in further detail by way of example. "Example 1"

Initially, titanium raw materials with the compositions shown in Table 1 (technically pure titanium) and Table 2 (titanium alloys) were cast using electron beam remelting (EPP, EVK) or plasma arc remelting (PDP, RAM) to obtain approximately rectangular ingots having a rough microstructure of the hardened product formed after casting. It should be noted that in the case of the source material with the symbol MOU v

The ingot corresponding to Table 1 was forged. It should be noted that "Mt", which represents the alloying component of the titanium source material in Table 2, means a mixed metal (an alloy containing a rare earth metal).

Then, a titanium stock having a thickness of approximately 120 mm, a width of approximately 250 mm, and a length of approximately 450 mm was cut from the ingot with designations other than MU and machined. Regarding the MO material, a titanium source material having a thickness of approximately 120 mm, a width of approximately 250 mm, and a length of approximately 450 mm was cut from the source material after forging. It should be noted that the respective cut source materials were cut in such a way that the positional relationship in terms of the position of the cut with respect to the ingot was consistent, and so that the positions in depth from the surface of the ingot were essentially the same.

Among the surfaces of the source materials (MI to M18) that were cut off, the surface (one side) designated as the rolled surface during hot rolling, which is described later, was machined on a two-roll type machining machine (see Figure 5) using the appropriate rolls , having protrusions with the shapes and placement configurations shown in

Table ZA, Table 4A and Table 5A, with the formation of dimples in the surface of the starting material and obtaining a processed titanium product. At this time, processing was carried out under process conditions such as amount (0) of indentation and processing temperature, which were variously changed as shown in Table 3A, Table 4A, and Table 5A. It should be noted that the protrusions were arranged to be staggered in top view as shown in the drawings from Figure b(a) to Figure b(c). In addition, with respect to the A2 feedstock, the feedstock was processed using a roll (without protrusions) having a diameter of 300 mm.

Each treated titanium product was then heated for approximately two hours at a temperature below the p-transformation point and then hot rolled to a thickness of approximately b mm using a continuous hot rolling strip mill. This hot-rolled sheet was blast-blasted and, in addition, allowed to pass through a continuous pickling line containing a mixture of nitric and hydrofluoric (fluoric) acids for pickling and scale removal. After that, surface defects that appeared, detected by visual inspection, were noted, and the condition of the appearance of surface defects was evaluated. Here, the term "transformation point" refers to the lower temperature limit at which the titanium starting material becomes B-single-phase upon heating.

More specifically, with respect to the hot-rolled sheet after passing through the continuous pickling line, excluding the sections that did not set, at the front and rear ends in the rolling direction, the length of the hot-rolled sheet was segmented into 200 mm intervals, and the ratio obtained by dividing the number of sections with the sections , where surface defects were detected, for the total number of sections (40 sections), was determined as the degree of formation of surface defects. According to the degree of formation of surface defects, the value of 0 95 was graded as "OO", small surface defects with a degree of more than 0 95 to 5 95 or less, and with a size of about 1 mm, were graded as "O", and large surface defects in numbers greater than 5 95 or with a size of approximately 10 mm or more were scored as "x". It should be noted that the symbols "O" and "O" mean "those who passed" the assessment and "x" means "those who failed" the test.

In Table 3B, examples of technically pure titanium are shown in comparison with comparative examples, and in Table 4B8, examples of titanium alloys are shown in comparison with comparative examples. The processing temperature of each processing roll was room temperature.

In addition, Table 58 shows examples in which, during hot processing, the source material was heated at a temperature of 100 to 400 2C, and the source material was subjected to processing in the process of uneven forming using a roll.

Based on the tables from Table 3A to Table 5B, it is found that when the raw material is subjected to rolling with a roll on which the protrusions are placed within the pitting range of the present invention, the degree of surface defect formation is 5 95 or less, which is low, and within an additional preferred range of conditions, the degree of surface defect formation can be reduced to 0 95.

On the other hand, it was found that relative to the comparative examples, which are examples of situations where the raw material was subjected to rolling as is without processing, cases where there were no protrusions on the surface of the rolls, and cases where the radius (K) of curvature of the protrusions, the value ( 0) indentation or the distance (5) between the centers of the protrusions are outside the range according to the present invention, the degree of formation of surface defects is high for each comparative example.

In particular, in samples A14 and A15, in which the distance (5) between the centers of the protrusions deviates from the range from 2(Н2-(8-0)2)12 to 3(Н82-(8-0)2)!2 (the range from 211 to Zg1), compared to AT, which is not processed, and A2, which was rolled using a roll without protrusions, although the degree of formation of surface defects decreased to about 20 95, it did not reach 5 95 or less.

Furthermore, as will be understood from the samples C1 to C20 which are examples, it was found that even when the processing temperature was within the range of 100 to 400 es, the same effect as that obtained at room temperature was obtained.

In the samples of ATO and A177, which are examples in which crimping was carried out by two-pass rolling using a roll in which predetermined protrusions were placed, the effect according to the present invention was obtained.

In AZZ, which is a comparative example, in which the source material obtained by forging the MOU ingot was subjected to hot rolling, the degree of formation of surface defects was 48 95, which is high. On the contrary, in A41, which is an example, rolling this raw material using a roll in which predetermined protrusions are placed, the effect of reducing the degree of formation of surface defects to 0 95 was obtained.

Table 1

Method Chemical composition (wt. Uo

Designation| obtaining Notes material | ingot, etc. Ee MSN Ti and d.

MI EVV 0.054 | 0.026 | 0.0038 | 0.0024 | 0.0021 | the rest is pure titanium

LB1 type

M2 EVV 0.092 | 0.058 | 0.0033 |0.0035| 0.002. | the rest is pure titanium

L52-type

M EVV 0.193 | 0.085 | 0.0025 | 0.0041 | 0.0022 | the rest is pure titanium

LZZ-type

Ma EVV 0.322 | 0.185 | 0.0090 | 0.0044 | 0.0020 | the rest is pure titanium

LZa-type 0.133 | 0.047 | 0.0032 |10.0020| 0.0027 the rest |А5ТМ аг2 0.265 | 0.122 | 0.0550 10.0045| 0.0027 rest / TAB5TM ag.Z 0.345 | 0.275 | 0.0045 10.0055| 0.0036 rest / TA5TM Sg.A

Forged Pure Titanium

EVV - a method of electron beam remelting

RAM - a method of plasma-arc remelting

Table 2 p Method of determination, Gru manny

MI EVV | - | - | -1 - 1 -|-1006| - | - resolve

MI EVV | - | - 105) - / -|- | - |005| - resolve

MmIi2 EVV | -|-1-1- 1 -/-1 - |005| 0003

MIZ RAM (| - (05 -| - /-|-1|- | - | - solution

MI4 RAM (| -(|10Y-|- 1 -1|-1- | - | - resha

MI5 RAM (| - 110 -| - - 105 - | - | - solution

MI6E RAM | - |10| - (030 710|02| - | - | - solution

MI7 EVV /05| - | - (045) - | -| - | - | - the decision was made by EVA /09| - | - (09551 - | - | - | - | - resolution

ЕВЕ is a method of electron beam remelting

RAM - a method of plasma-arc remelting

Table ZA

Performance characteristics Processing conditions

Forms of the High Council. Distance ius Distance a High) and ! | I have (B) Plan)| is 5. poper and NINati|chas . ; between |The magnitude of Yu

Form of cry. rny | between the temperature of each peak and the rows of the peaks of the radius processing center o upu |Ipoveiar i i (mm) «ny : g (mm)| amy pereri (mm (mm) | rhni (mm (mm) protrusion from (mm) | ) iv (mm) without finishing -Г-Г1-1-1-1-1-11- 1 - . room

A giv 511 3 emporayuura temperature head 7 temperature

A A Spherical | Fig. 3 5 with | 2 Z 7 7 2 room head 7(r temperature

A 5 Spherical | Fig. with 5 with |2 with 7 7 with room head 7(r temperature

A Spherical | Fig. BI in 5 5 10 10 2 room head 7«a) temperature

A 7 Spherical | Fig. B 7 B |2 5 13 13 5 room head 7(r temperature

A Spherical | Fig. 10125125 15 15 4 room head 7«a) temperature

A Spherical | Fig. 105 2 | from 18 18 2 room head 7(r temperature

A 10 Spherical | Fig. 10125125 15 15 2 (1 mmx2 |room head 7"a) passages) |temperature

A 14 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A 12 Spherical | Fig. 101510 | 5 10 26 26 5 room head 7(r temperature up to (13 |Spherical |Fii |30|h5|h0|5| 0 | 26 | 26 10 /Room head 7(r temperature head 7 temperature up to |45|Spherical |Fig |30|. 10 |. 35 room head 7(r temperature x rereue ro ee 111212 DE head 7(r temperature

A 17 Spherical | Fig. 15 45 z 32 20 20 Z (1.5 mmx2 | room head 7(r passes) | temperature cache vivrt yr in Ted. head 7(r temperature cache vivrt yr ni ti t0Penya. head 7(r temperature head 7(r temperature head 7(r temperature head 7(r temperature head 7 temperature

A 24 Spherical | Fig. For! i5BI 0 | 5 z0 63 63 5 room head 7(p temperature up to o|o5|Spherical |Fii |5o0| 5140) 5| from | is6 with | 63 10 | Room head 7(r temperature without processing -Г-Г1-1-1-1-1-11- 1 - without processing -Г-Г1-1-1-1-1-11- 1 - without processing - Г-Г1-1-1-1-1-11- 1 - without processing -Г-Г1-1-1-1-1-11- 1 - without processing -Г-Г1-1-1-1-1-11- 1 - without processing -Г-Г1-1-1-1-1-11- 1 - without processing -Г-Г1-1-1-1-1 -11- 1 - without processing -Г-Г1-1-1-1-1-11- 1 -

And for Spherichna |Fiig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A z5 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A 36 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A 37 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A z8 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A 39 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature

A 40 Spherical | Fig. evil! 5 | 5 87 20 20 5 room head 7(r temperature head 7 temperature

And to Sferichna |Fiig. 104 A 20 14 you room head 7"a) temperature

A 43 Spherical | Fig. 104 A 1451 14 you room head 7«a) temperature

Table ZV 11111111 Pit | The results of the assessment of surface . Distance of defects after: Radius Planar Distance O between etching,

Material B: : P between . Notes radius g1 in rows of Igaryachedan plate of curvature (mm) centers!) dimples Manifestation (mm) (mm) (mm) (|surface| Evaluation of defects example ag 1-17, 1 vo» | horde example example invention invention

Arvimi 5 | I am | | 1 ozh | input invention invention

Arvimi tyu | I am in | 6 la | Horde is an example

Areimi tyu | in | TV 6 ozh | input by invention

Aroma | 1 in | 5 | 5 10» 2 ayu invention invention invention invention example example invention

Artmi 15 | in | about | oh o | entrance invention invention invention invention invention invention invention example azam | | 3111" | vd

Table 4A

Performance characteristics Processing conditions

Av Dist

And High High | Plan) Distance| Ann I. led

Form)! Glad to see you. rank ota a | arny an 5) between

Form poper/us V H click time| and between | series p Temperature of the river) KnOi curve. the row pretended to be the top of the peninsula) from the height pove TIN radio, we are the center | luva processing from | (mm) upu rhni ar| sg amy |whistle| nya (mm) (mm! (mm)| (mm)| half (mm) (mmu| im)

In | 1 | without processing - G-1-1-1-1-1-1-1 -

B 2 | without processing - G-1-1-1-1-1-1-1 -

In Z | without processing - G-1-1-1-1-1-1-1 -

B 4 | without processing - G-1-1-1-1-1-1-1 -

B 5 | without processing - G-1-1-1-1-1-1-1 -

B 6 | without processing - G-1-1-1-1-1-1-1 -

B 7 | without processing - G-1-1-1-1-1-1-1 -

B 8 | without processing - G-1-1-1-1-1-1-1 -

IV | 9 |without processing -G-1-1-1-1-1--171 -

era Ge ee ze head 7(r temperature etveshe in measurements from head 7(r temperature 12 Spherical ery ve vy min zd head 7(r temperature

Spherical | Fig. 10.1 z0 5 vB| 87 20 20 5 Room head 7(r temperature top ve xvi shi head 7(r temperature eGlvsheel ee ryu she head 7 temperature eGevshshet 1" 19 2111191 with no head 7(r temperature

Table 48 11111111 Pit | Evaluation results. surface defects

Radius Planar The distance between the distances after etching

Materials Vi ar P between hot-rolled plate Notes radius g1 rows of curvature centers Manifestation (mm) of dimples. (mm) . defects ge 171 oh example efe 17111 example ee 171711 ryuh example re 171 example re 1 7111 i example bere 17111 i example re 17111 i example ee 1 7111 i example ee 1111 example zr 1 winx about invention ee (em oh 11 sho invention ze ger » oh |. day invention ze 20 096

GOGG11111111111111111111111111117invention./7/ know ||» It's a great invention tyu | in | tho | go o» |» self-invention

Table 5A processing

Distance

Radi Vys Vysot| Near Plani) Distance anh G. led

Form ad ota ay | ma arny|an 5) between chin) Temp transverse us V n |Matysrchas! and between | of the O |erat series

The shape of the top of the KNOi curves | tin press the radio button the center and we Izny believe Ryuvan | diameter of the cross-section (mm) UPU| uni (mm st | ami vystu) i bky (mm) (mu | ) (mm)| (mm)| half (mm) (mm)

So | 6 (Spherical head |Fig.7(5) | 10 |10| 5 5187 20 | 20 | 5 | goo

C | 8 (Spherical head |Fig.7(5) | 10 |10| 5 5187 20 | 20 | 5 | goo

C 9 (Spherical head | Fig.7(5) | 10 |10| 5 5187 20 | 20 | 5 | goo

Table 5B 11111111 Pit | Evaluation results. surface defects

Radius Planar Distance Distance after etching

Materials Vi ar P between hot-rolled plate Notes radius g1 rows of curvature centers Manifestation (mm) of dimples. defects invention invention invention invention invention cm ovo oo | 8 by invention by invention s|v|me ovo oo 8 by invention I dare in ooo | with invention invention invention invention invention invention invention invention invention invention invention invention

LIST OF REFERENCE ITEMS

1, 2, 3, 4 - titanium raw material (slab, bloom, ticket)

Ta, ha, Za, 4a - surface 16, 20, ZB, 4r - hole 1r1, 2B1, ZB, 4B: - the bottom of the hole

Ba - roll b, ba, 60, bs, ba - protrusion

Claims (1)

FORMULA OF THE INVENTION 1. A method of producing a machined titanium product, wherein the titanium source material is passed through a gap between a pair of rolls, wherein at least one roll of the pair of rolls has protrusions arranged to be staggered when the surface of the roll is fully formed, and viewed at top view, and the method includes the process of forming numerous dimples in the surface of the titanium source material by pressing protrusions into the surface of the titanium source material, while each protrusion includes a spherical pressure surface at the front end of the protrusion, and when the height of the pressure surface is represented by the value Пп (mm), the radius of curvature of the pressure surface is represented by the value K (mm), the center-to-center distance between the protrusions bordering the direction in which the titanium source material passes is represented by the value 5 ( mm), and the value of indentation by protrusions is represented by the value O (mm): K has a value within the range from 3 to 30; p has a value within the range from 2 to 10, and is Пп or less; and З has a value within the range from 2(K2-(8-0)2)!2 to 3(K2-(8-0)2)12, 2. The method according to claim 1, in which, when the distance between each row in which the protrusions are placed, is represented as I. (mm), GI value. is within the range from 2(B2-(8-0)2)!2 to З(Е2-(В-р), 3. The method according to claim 17 or 2, in which the dimple formation process is performed in a state in which the temperature of the surface of the titanium source material is a temperature that is 0-500 76. Zh de Mytya ZhK ke sh ek schu zh Zk t shk yah Mev I yak ek. KY І X hХTE БАЛИ s Moh Kv and Ks M I and I te p tovoi b MY I shk VC BK B TT UMH : U Ku i GT KZ M : Z 4 Mu start Kak cheny, ony tin snu nya 3 i g tech A iz - y Ta i A iz Ko Za Mak Shi Fut I ; opr her SUYA KK i and. 5 Yes, they are the same: ZOO ne ze I ov SYA yav EY y osn ki -kshii yi --yi in I y Za 2 Fig. 1 15. and I. 4, 16; a, eV. 45, her. and; hmm Yaa SovuavidvYav ate and in pri teee itrirOr-y still So tent zhov nya maje pudkttti nya nen Kunis thanks tya tenty nka ref Husa khuztin zhetyaayaeti nya; ZhK ': gi ;. Shi! zr Zv Zk dya Zshe 03 be and vda Zh.O ih i ia, ba, ba Fig. 2. and 5 or Kk o: i KO same. Street Fut» HOW KA I nya o, zi Kk | that's the same She I look and there is Y PAK AT ni sere KOYU a I M r stand and well 1 si a and i . 5 GT and і і ч ю Ye had a with . I vyy and 1 ho E ' n ' A AH I M 1 and era oayukktrni zhi Ba: Fig. From the tree and | however, I entered; 5th day of the Seine Day, Fig. 4