WO2019054303A1 - Production method for titanium or titanium alloy green compact - Google Patents

Abstract

A production method for a titanium or titanium alloy green compact. The production method uses a cold isostatic press to produce a titanium or titanium alloy green compact that has a relative density of at least 80%. The production method uses a CIP mold 1 that: is 0.5–1.5 mm thick; has a mold thickness error range index α of 0–0.05, given by (maximum thickness-minimum thickness)/(maximum thickness+minimum thickness) when the thickness of the mold is measured at 10 arbitrary points in the longitudinal direction thereof; comprises a thermoplastic resin that has a compressive modulus of elasticity of 800–2,100 MPa and a Shore D hardness of 78–85; and has a powder supply port and a cavity for filling with powder.

Description

Method of producing titanium or titanium alloy green compact

The present invention relates to a method for producing a titanium or titanium alloy green compact.

Although titanium and titanium alloys have excellent mechanical properties, they are difficult to process and complex shaped products have been conventionally manufactured by cutting. However, in the case of manufacturing by cutting, there is a problem that the yield is bad and the product unit price becomes very high.

As one of the methods of solving the said problem, the method of manufacturing titanium and a titanium alloy green compact using an elementary powder mixing method is known. In the elementary powder mixing method, pure titanium powder and a powder for alloying element addition are mixed at a predetermined ratio, filled into a mold, compacted at room temperature, and then sintered or cold isostatic press (CIP) ) Processing method etc.

For example, in JP-A-7-90313, a thermoplastic resin is used to prepare a powder molding die by a blow molding method, the powder molding die is filled with titanium powder, and molding is performed using a hydrostatic pressure press. Thus, a method of producing a compact of titanium powder is described. JP-A-2010-188711 describes a method for producing a bottomed cylindrical container in which a bottomed cylindrical container is stretch blow molded from a thermoplastic resin preform.

JP 7-90313 A JP, 2010-188711, A

However, according to the method of blow molding thermoplastic resin as exemplified in Patent Documents 1 and 2 to form a molded article, a high-density molded article can be obtained without cracking, but it is difficult to obtain accurate thickness. Therefore, the titanium or titanium alloy green compact manufactured using the molded object manufactured by blow molding becomes easy to produce a gap in an outside dimension. Although there is also a method of using a metal mold or the like in order to improve the accuracy of the outer dimension, it becomes expensive and it becomes difficult to manufacture a complicated shape.

In view of the above problems, the present invention provides a method for producing a titanium or titanium alloy green compact capable of producing a titanium or titanium alloy green compact having a complicated shape with high accuracy of external dimensions more economically. Do.

As a result of intensive studies, the present inventors have found that it is useful to use a CIP molding mold having a predetermined thickness range and thickness accuracy using a thermoplastic resin having predetermined characteristics. Obtained.

The present invention completed on the basis of the above findings is, according to one aspect, a method for producing a titanium or titanium alloy green compact from which a titanium or titanium alloy green compact having a relative density of 80% or more is obtained using a cold isostatic press. It is expressed by (maximum value-minimum value) / (maximum value + minimum value) when thickness is 0.5 to 1.5 mm and thickness of any 10 points in the longitudinal direction of the mold is measured. Mold thickness error range index 0 is 0 to 0.05, compression elastic modulus is 800MPa to 2100MPa, Shore D hardness is 78 to 85, and it is made of thermoplastic resin, and powder supply port and cavity for powder filling There is provided a method for producing a titanium or titanium alloy green compact characterized by using a CIP molding mold having

In one embodiment, the method for producing a titanium or titanium alloy green compact according to the present invention is such that the CIP molding mold is continuous with the large diameter portion and the large diameter portion and the cross-sectional area of the horizontal cross section is smaller than that of the large diameter portion. A ratio D of the smallest diameter of the small diameter portion to the largest diameter of the large diameter portion in the horizontal cross section (small diameter portion smallest diameter / large diameter portion largest diameter) is at least 0.5 and less than 0.8. .

In another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, in the CIP molding mold, the outer surface of the small diameter portion is inclined with respect to the outer surface of the large diameter portion, An angle θ between a straight line extending in the extending direction of the outer surface of the large diameter portion from the end of the outer surface and the outer surface of the small diameter portion is 10 degrees or more and less than 60 degrees.

The method for producing a titanium or titanium alloy green compact according to the present invention, in yet another embodiment, includes producing a CIP molding mold using a 3D printer device.

The method for producing a titanium or titanium alloy green compact according to the present invention includes, in yet another embodiment, producing a CIP molding mold using a 3D printer apparatus utilizing a material extrusion method.

The method for producing a titanium or titanium alloy green compact according to the present invention includes, in yet another embodiment, producing a CIP molding mold using a 3D printer apparatus utilizing a material injection method.

In still another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, 80 to 100% by mass of pure titanium powder having an average particle diameter of 30 μm or more and less than 100 μm is filled in a cavity of a mold for CIP molding To do.

In still another embodiment of the method for producing a titanium or titanium alloy green compact according to the present invention, a pure titanium powder having an average particle diameter of 30 μm to less than 100 μm, and an alloy element powder or a master alloy having an average particle diameter of 5 μm to less than 50 μm. 1 to 20% by mass of the powder is included in the cavity of the CIP mold.

According to the present invention, it is possible to provide a method for producing a titanium or titanium alloy green compact which can produce titanium or titanium alloy green compact having a complicated shape with high accuracy of external dimensions more economically.

It is sectional drawing which shows an example of the mold for CIP shaping | molding which concerns on embodiment of this invention, and the measurement position (arbitrary ten points | pieces) of the thickness of the mold for CIP shaping | molding which is this example. FIG. 2 (a) is an explanatory view for explaining an inclination angle θ of the large diameter portion and the small diameter portion of the CIP molding mold according to the embodiment of the present invention, and FIG. (B) is an example in case a small diameter part has a slope of a curved surface shape.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment shown below is an example of an apparatus and method for embodying the technical idea of the present invention, and the technical idea of the present invention includes the structure, arrangement, and the like of components as described below. It does not identify.

The method for producing a titanium or titanium alloy green compact according to an embodiment of the present invention is a method for producing titanium or titanium alloy green compact having a relative density of 80% or more using a cold isostatic press (CIP) A CIP molding mold 1 having a powder supply port 2 and a powder filling cavity 3 as illustrated in, for example, FIG. 1, which is a method for producing an alloy powder compact, can be used.

In order to manufacture a titanium or titanium alloy green compact having a high accuracy in external dimensions and a complicated shape, the material of the CIP molding mold 1, the compression modulus, and the Shore D in relation to the manufacturing process of the CIP treatment It is necessary to adjust the hardness to an appropriate range and to increase the accuracy of the thickness and thickness of the CIP molding mold 1.

Specifically, the CIP molding mold 1 according to the present embodiment needs to have a thickness of 0.5 to 1.5 mm. If the thickness is less than 0.5 mm, the CIP molding mold 1 may be deformed by the weight of the filling powder, and the dimensional accuracy may be reduced. On the other hand, if the thickness is greater than 1.5 mm, the springback force of the CIP molding mold 1 at CIP unloading may be greater than the green compact strength, and breakage of the green compact may occur.

As for the dimensional accuracy of thickness, the mold thickness error range index α represented by (maximum value-minimum value) / (maximum value + minimum value) when the thickness of any 10 points in the longitudinal direction of the mold is measured Is preferably from 0 to 0.05. When evaluating the dimensional accuracy of the thickness, if the measurement points of the thickness are locally biased, the variation in the thickness of the CIP molding mold 1 as a whole may not be properly evaluated. Therefore, in this embodiment, it means a place obtained by equally dividing the longest surface of the CIP molding mold 1 into ten as measurement points of “arbitrary 10 points of thickness”. For example, as shown in FIG. 1, the CIP molding mold 1 is allowed to stand on a horizontal surface so that the longitudinal direction along the maximum length of the CIP molding mold 1 is perpendicular to the horizontal surface, and a direction perpendicular to the horizontal surface The thickness at each position (1 to 10) obtained by equally dividing the CIP molding mold 1 into 10 can be measured.

That is, as shown in FIG. 1, “mold thickness error range index α” is an arbitrary height of each height when CIP mold 1 is equally divided into 10 along the longitudinal direction of CIP mold 1. The thickness of the measurement point at the position is measured, and the maximum value and the minimum value are used to indicate the error range index evaluated. The thickness can be measured, for example, by using a digital caliper or the like for each measurement point.

When the mold thickness error range index α becomes larger than 0.05, the accuracy of the external dimensions of the titanium or titanium alloy powder compact manufactured using the CIP molding mold 1 is deteriorated and the control of the springback force is also performed. Becomes difficult and cause breakage. The mold thickness error range index α is preferably 0.03 or less, more preferably 0.01 or less, and still more preferably 0.005 or less.

If the target thickness of the CIP molding mold 1, that is, the thickness data of the CIP molding mold 1 at the time of manufacture is known, evaluate the dimensional accuracy of the CIP molding mold 1 by the mold thickness error range index β. You can also. Similar to the measurement of the mold thickness error range index α, the mold thickness error range index β is a measurement point at any position of each height when divided equally into ten along the longitudinal direction of the CIP molding mold 1 It refers to “(maximum value−minimum value) / target thickness” when the thickness of each is measured. As the target thickness, for example, the thickness of three-dimensional CAD original data at the time of molding of the CIP molding mold 1 can be used.

When the mold thickness error range index β becomes larger than 0.5, the accuracy of the external dimensions of the titanium or titanium alloy powder compact manufactured using the CIP molding mold 1 is deteriorated and the control of the spring back force is also performed. Becomes difficult and cause breakage. The error of the mold thickness error range index β of 0.5 or less does not affect the physical properties of the CIP molding mold 1. The mold thickness error range index β is preferably 0.3 or less, more preferably 0.1 or less, and still more preferably 0.06 or less.

Alternatively, the absolute value of any 10 points (thickness / target thickness × 100-100) of each height when CIP mold 1 is equally divided into 10 along the longitudinal direction of CIP mold 1 The average value of can also be evaluated as a mold thickness error range index γ. The mold thickness error range index γ is preferably less than 1.5, more preferably 1.0 or less, and still more preferably 0.5 or less.

As a material used for the mold 1 for CIP molding, a thermoplastic resin is preferable, and for example, acrylic resin, polylactic acid (PLA) resin, etc. can be suitably used. The compressive elastic modulus of the thermoplastic resin material is preferably 800 MPa to 2100 MPa. If the compressive elastic modulus is less than 800 MPa, the spring back of the CIP molding mold 1 during CIP unloading may be large, which may lead to green powder fracture. If the compressive elastic modulus is too low, the rigidity of the CIP molding mold 1 may not be sufficient, and the CIP molding mold 1 may be deformed by the own weight of the filling powder, and the dimensional accuracy of the CIP molded product may be significantly reduced.

On the other hand, when the compressive elastic modulus is larger than 2100 MPa, the rigidity of the CIP molding mold 1 becomes high, and the load is not sufficiently transmitted to the internal powder at the time of CIP processing pressurization, and titanium or titanium alloy green compact having a relative density of 80% or more Can not get. The compressive elastic modulus of the thermoplastic resin used for the CIP molding mold 1 is more preferably 1000 MPa to 1900 MPa, still more preferably 1500 MPa to 1900 MPa. The compressive elastic modulus can be measured by a test method in accordance with JIS K7181 (2011).

The Shore D hardness of the thermoplastic resin used for the CIP molding mold 1 is preferably 78 to 85, and more preferably 80 to 83. When the Shore D hardness is less than 78, the CIP molding mold 1 is deformed by the weight of the filling powder, and the dimensional accuracy is reduced. When the Shore D hardness is greater than 85, the rigidity of the CIP molding mold 1 becomes high, and the load is not sufficiently transmitted to the internal powder at the time of CIP processing pressurization, and a titanium or titanium alloy green compact having a relative density of 80% or more is obtained I can not do it. Shore D hardness can be measured by a test method in accordance with JIS K 7215 (1986).

As shown in FIG. 1, the CIP molding mold 1 is continuous with the large diameter portion 11 and the large diameter portion 11 and has a small diameter portion 12 having a smaller horizontal cross-sectional area than the large diameter portion 11 and a smaller diameter portion 12 The cross section of the horizontal cross section is also large, and it includes a large diameter portion 13 continuous with the small diameter portion 12 and a top portion 14 continuous with the large diameter portion 13 and having a powder supply port 2 at the top.

In the small diameter portion 12, the cross-sectional area in the horizontal direction gradually decreases from the bottom to the top, and the cross-sectional area in the horizontal direction gradually increases from the middle portion of the small diameter portion 12 toward the large diameter portion 13. It can have a shape.

In the large diameter parts 11 and 13, the horizontal cross section may have a polygonal shape, or the horizontal cross section may be circular or elliptical, and can be appropriately changed according to the use application, and the specific shape Is not particularly limited. The ratio D of the minimum diameter D ₁₂ of the small-diameter portion 12 to the maximum diameter D ₁₁ of the large diameter portion 11, 13 in the horizontal section (small-diameter portion minimum diameter D ₁₂ / large diameter portion maximum diameter D _11), 0.5 or 0. It is less than eight. The shapes of the large diameter portions 11 and 13 and the small diameter portion 12 preferably have substantially similar shapes in horizontal cross sections, but may have shapes different from each other.

As shown in the enlarged view of FIG. 2A, in the CIP molding mold 1, the outer side surface 121 of the small diameter portion 12 is inclined with respect to the outer side surface 111 of the large diameter portion 11. An example of an angle θ (FIG. 2A) between a straight line X extending from the end 112 of the outer surface 111 of the large diameter portion 11 to the outer surface 111 of the large diameter portion 11 and the outer surface 121 of the small diameter portion 12 Then, the angle θ) between the straight line X and the outer surface 121 of the small diameter portion 12 when measured counterclockwise from the straight line X is 10 degrees or more and less than 60 degrees. When the outer surface 121 of the small diameter portion 12 has a curved surface, as shown in FIG. 2B, the position where the minimum diameter D ₁₂ is in the horizontal cross section of the small diameter portion ₁₂ and the end 112 of the large diameter portion 11 The angle θ between the straight line Y passing through the straight line X and the straight line X (that is, the angle between the straight line X and the straight line Y when measured counterclockwise from the straight line X based on the straight line X) is 10 degrees or more and less than 60 degrees.

The CIP molding mold 1 having a complicated shape as shown in FIGS. 1 and 2 (a) and 2 (b) can be manufactured using a 3D printer. Thereby, the thickness can be made uniform, and the dimensional accuracy can be improved, as compared with the case where the mold is formed by blow molding as in the prior art. Moreover, since it is not necessary to manufacture a mold etc. in the case of manufacture of a mold, the mold 1 for CIP molding which has a complicated shape more economically can be manufactured so that a dimensional accuracy may become high.

Although a general-purpose device can be used as the 3D printer device, it is preferable to use a 3D printer device using a material extrusion method or a 3D printer device using a material injection method.

The titanium according to the present embodiment is implemented by filling pure titanium powder or pure titanium powder and alloy element powder or mother alloy powder in the cavity 3 in the CIP molding mold 1 according to the present embodiment and performing CIP processing. Or a titanium alloy green compact is obtained. Here, the alloying element powder is a powder of a single element such as Al powder or V powder, and the mother alloy powder is a powder containing a plurality of elements.

As a filler, for example, 80 to 100% by mass of pure titanium powder having an average particle diameter of 30 μm or more and less than 100 μm, and filled in a cavity of a CIP molding mold, titanium or titanium alloy green compact having a relative density of 80% or more Is obtained. Alternatively, 1 to 20 mass% of pure titanium powder having an average particle diameter of 30 μm or more and less than 100 μm and alloy element powder or mother alloy powder having an average particle diameter of 5 to 50 μm is filled in the cavity 3 of the CIP molding mold 1 By performing the CIP process, a titanium or titanium alloy green compact having a relative density of 80% or more can be obtained. In addition, an average particle diameter points out the value of particle diameter D50 (median diameter) of the particle size distribution (volume basis) obtained by the laser diffraction scattering method. Powder filling and CIP treatment can be carried out using generally well known conditions. In the present embodiment, "pure titanium" means industrial pure titanium that satisfies the composition defined in JIS II. The main alloy systems used for titanium alloy compacts include Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-2Sn-4Zr-6Mo, Ti. And -10V-2Fe-3Al.

According to the titanium or titanium alloy compact according to the embodiment of the present invention, a CIP molding mold whose thickness and thickness accuracy are controlled using a predetermined thermoplastic resin using a 3D printer By obtaining C.1 and performing CIP processing using this, it is possible to manufacture a titanium or titanium alloy green compact having high accuracy of external dimensions and a complicated shape more economically.

Examples of the present invention and comparative examples are described below, but the present invention is of course not limited to the following examples.

Based on 3D data of CIP molding mold whose thickness is adjusted between 0.5 and 1.75 mm, using 3 types of resin (PLA resin, acrylic resin, silicon resin), for CIP molding by 3D printer A mold was made. The CIP molding mold using PLA resin was manufactured by a material extrusion method using a 3D printer apparatus Kuria, manufactured by Kubo Metals Co., Ltd. The CIP molding mold using an acrylic resin was manufactured by a material injection method using a 3D printing apparatus ProJet 3600MAX manufactured by 3D Systems. The silicone resin material was manufactured by a material injection method using a Keyence 3D printer AGILISTA-3200. The ratio D of the large diameter portion to the small diameter portion of the CIP molding mold is 0.6, the angle θ between the large outer diameter and the small outer diameter is set to 27 degrees, and the CIP molding mold having the shape shown in FIG. Made.

A hollow in the produced CIP molding mold was filled with Tohotec pure titanium powder TC-150 (particle size width 45-150 μm, average particle size 90 μm) and subjected to CIP treatment. For the CIP process, a cold isostatic pressing apparatus CL4-22-60 manufactured by Nikkiso Co., Ltd. was used.

A hollow in the produced CIP molding mold is filled with pure titanium powder, tapped, vacuum-packed one sealed with a vinyl tape, and the vacuum-packed pure titanium powder-filled product is set in a cold isostatic molding machine And pressurized. After reaching about 300 MPa, after holding for 1 minute, pressure was released, and the titanium powder-filled product was removed from the cold isostatic pressing apparatus. The obtained molded product was heated at 130 ° C. for 15 minutes at atmospheric pressure, and the softened mold for CIP molding was removed using a cutter, nipper or the like to obtain a green compact.

Mold thickness error range indexes α, β, γ, compressive modulus, Shore D hardness, and green density (relative density) were measured for CIP molding molds produced using each material and each device. Target thickness used thickness at the time of 3D data creation. The CIP molding mold 1 was divided into 10 equal parts in the longitudinal direction (in this example, 12 mm intervals), and the thickness of 10 points was measured with a tic-ness gauge. The compressive elastic modulus was calculated from the measurement result implemented based on JISK7181 (2011). Shore D hardness was measured in accordance with JIS K 7215 (1986). The green density was calculated from the density / theoretical density 4.51 / cm ³ × 100 obtained by the Archimedes method. Furthermore, the presence or absence of breakage of the obtained green compact was observed. The results are shown in Table 1.

In Comparative Examples 1 and 2 in which a CIP molding mold having a thickness of 1.75 mm, which was outside the range of 0.5 to 1.5 mm in thickness, was produced, although the mold could be produced, the pressure of titanium or titanium alloy was used. The powder was broken and the desired green compact could not be produced. In Comparative Examples 3 and 4 using a silicone resin whose compressive elastic modulus and Shore D hardness were out of the range of the present invention, it was not possible to produce a CIP mold. In the comparative example 5, although the mold was able to be produced, the shape after powder filling was not able to be maintained at the time of CIP processing by lack of intensity | strength. On the other hand, in Examples 1 to 4, it was possible to produce a green compact having a relative density of 80% or more and no breakage.

DESCRIPTION OF SYMBOLS 1 ... CIP molding mold 2 ... powder supply port 3 ... cavity 11 ... large diameter part 12 ... small diameter part 13 ... large diameter part 14 top part 111, 121 ... outside surface 112 ... end part

Claims (8)

A method for producing a titanium or titanium alloy green compact, comprising obtaining a titanium or titanium alloy green compact having a relative density of 80% or more using a cold isostatic press,
Mold thickness represented by (maximum value-minimum value) / (maximum value + minimum value) when the thickness is 0.5 to 1.5 mm and the thickness of any 10 points in the longitudinal direction of the mold is measured CIP comprising a thermoplastic resin having an error range index α of 0 to 0.05, a compressive elastic modulus of 800 MPa to 2100 MPa, and a Shore D hardness of 78 to 85, and having a powder supply port and a cavity for powder filling A method for producing a titanium or titanium alloy green compact characterized by using a molding mold. The CIP molding mold comprises at least a large diameter portion and a small diameter portion continuous to the large diameter portion and having a smaller cross sectional area in horizontal cross section than the large diameter portion, and the largest diameter portion in the horizontal cross section The titanium or titanium alloy compact according to claim 1, wherein the ratio D of the minimum diameter of the small diameter portion to the diameter (small diameter portion minimum diameter / large diameter portion maximum diameter) is 0.5 or more and less than 0.8. How to make the body. In the CIP molding mold, the outer surface of the small diameter portion is inclined with respect to the outer surface of the large diameter portion, and the outer surface of the large diameter portion extends from the end of the outer surface of the large diameter portion. The method for producing a titanium or titanium alloy green compact according to claim 1 or 2, wherein an angle θ between the straight line extending in the direction and the outer surface of the small diameter portion is 10 degrees or more and less than 60 degrees. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 3, comprising producing the CIP molding mold using a 3D printer device. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 3, comprising producing the CIP molding mold using a 3D printer apparatus utilizing a material extrusion method. The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 3, comprising producing the CIP molding mold using a 3D printer apparatus utilizing a material injection method. The titanium or titanium alloy according to any one of claims 1 to 6, which comprises filling 80 to 100% by mass of pure titanium powder having an average particle diameter of 30 μm or more and less than 100 μm into the cavity of the CIP molding mold. Production method of green compact. Filling 1 to 20% by mass of pure titanium powder having an average particle diameter of 30 μm or more and less than 100 μm and alloy element powder or mother alloy powder having an average particle diameter of 5 μm or more and less than 50 μm in the cavity of the CIP molding mold The method for producing a titanium or titanium alloy green compact according to any one of claims 1 to 6, which comprises.

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