RU2036046C1 - Method of pressure forming of materials - Google Patents

Abstract

FIELD: metal pressure forming. SUBSTANCE: method of forming metals and powder materials comprises steps of applying a deforming effort simultaneously to an upper end and a lateral surfaces of a blank; making an extrusion in a direction, being parallel with a direction of applying a main deforming effort; providing at this step a displacement of a material of the blank in a zone of its lower end with a rate, being determined according to a given relation. High grade of material of the blank volume in its lengthwise and lateral directions is provided due to uniform deformation of a structure by plastic shear, whose action is being realized simultaneously in two mutually normal planes, coinciding with directions of motion of a punch and walls of a container. EFFECT: enhanced quality of central zone of material of blank, being formed. 1 cl, 4 dwg

Description

 The invention relates to the processing of materials by pressure and relates to methods for manufacturing articles by pressing, which can be used in the processing of both porous and compact materials.

Known materials processing method comprising: heating the blank by deforming its impact punch at its end face with reciprocating it in a channel of constant cross section, consisting of two portions located relative to one another at an angle ^of 2-6, when subjected to the preform by other backpressure end [1]
The disadvantage of this method is the low quality of the product due to the uneven development of the metal structure of the workpiece in the transverse direction, since in this direction the material accumulates an unequal degree of shear deformation, and this unevenness increases with increasing number of cycles, reciprocating movements of the workpiece in the channels, and during processing porous materials there is an uneven distribution of density over the cross section of the product.

Closest to the invention is a method of processing metals, which consists in applying the main deforming force to the upper end of the workpiece with an additional force perpendicular to the main one to the side surface of the workpiece with subsequent extrusion of the workpiece material into the channels of the tool [2]
The disadvantage of this method is the low quality of the product due to the uneven development of the structure of the material of the workpiece in length, since the deformation of the front end of the workpiece in length occurs under the influence of mainly hydrostatic with a low dose of shear deformation, in contrast to the entire volume of the workpiece.

 The aim of the invention is to improve the quality of the parts by increasing the uniformity of material properties along their length.

λv_п где V_з скорость перемещения материала у нижнего торца заготовки, м/с;
V_п скорость перемещения материала у верхнего торца заготовки, м/с;
ρ_o, ρ_к- соответственно относительная исходная и конечная плотность материала заготовки, кг/м³;
λ- степень вытяжки, определяемая из условия;
λ

, где l_o исходная ширина заготовки, мм;
l₁ текущая ширина недеформированной части заготовки за фиксированный промежуток времени, мм.This is achieved by the fact that in the method of processing metals and powder materials, which consists in applying a deforming force to the upper end face of the workpiece, an additional force perpendicular to the main one to the side surface of the workpiece with subsequent extrusion of the material into the tool channels, according to the invention, the material is extruded in a direction parallel to the application of the main deforming force, while the movement of the workpiece material in the area of its lower end is carried out at a speed determined from the relationship:
v _s

λv _p where V _{s the} speed of movement of the material at the lower end of the workpiece, m / s;
V _{p the} speed of movement of the material at the upper end of the workpiece, m / s;
ρ _o , ρ _to - respectively, the relative initial and final density of the workpiece material, kg / m ³ ;
λ is the degree of drawing, determined from the condition;
λ

where l _{o the} initial width of the workpiece, mm;
l _{1 the} current width of the undeformed part of the workpiece for a fixed period of time, mm

 A qualitative study of the volume of the workpiece material in the longitudinal and transverse directions is caused by uniform deformation of its structure by plastic shear, which occurs simultaneously in two mutually perpendicular planes that coincide with the directions of movement of the punch and the container walls.

v_п, где l_o исходная ширина заготовки, мм;
h_o исходная высота заготовки, мм.The main relationship between the speed of movement of the workpiece in a direction perpendicular to the axial direction of deformation (lateral speed of the workpiece) and the speed of movement of the punch (axial speed of the upper end of the workpiece) is determined from the condition that the workpiece is completely filled with material, resulting from the movement of the walls of the channel container, taking into account changes in the relative workpiece density:
v _b

v _p where l _{o the} initial width of the workpiece, mm;
h _{o the} initial height of the workpiece, mm

будет происходит сдвиг одновременно в двух направлениях во всем объеме заготовки.In the case when

there will be a shift simultaneously in two directions in the entire volume of the workpiece.

>

преимущественно сдвиг имеет место в направлении перемещения пуансона.At

>

predominantly a shift takes place in the direction of movement of the punch.

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преимущественно сдвиг имеет место в направлении, перпендикулярном направлению перемещения пуансона.At

<

predominantly the shift takes place in a direction perpendicular to the direction of movement of the punch.

v_п а при l₁=l_o; λ=∞.The speed of movement of the metal at the lower end of the workpiece (supporting part) V _s depends on the amount of drawing, the relative density of the workpiece and the speed of movement of the punch). In turn, the degree of drawing is directly proportional to the speed of movement of the workpiece in the direction perpendicular to the speed of movement of the workpiece in the direction perpendicular to the axial strain force and varies from ∞ to 1. At the beginning of pressing, the degree of drawing is ∞, at the end, since in the absence of the speed of movement of the side surface of the workpiece l ₁ = 0 and λ = 1 when v _s

v _p a when l ₁ = l _o ; λ = ∞.

 In FIG. 1 shows a diagram of the implementation of the proposed method, the initial position; in FIG. 2, section AA in FIG. 1; in FIG. 3 intermediate position; in FIG. 4 end position.

 The method is carried out in a device that includes a punch 1 for applying a deforming force, a container 2 configured to move in a direction perpendicular to the direction of application of the deforming force.

 Planks 3-5 are installed in the cavity of the container, creating, together with a portion of the inner surface A of the container 2, a cavity for accommodating the workpiece. Planks 3-5 are made with the possibility of movement together with the container and with the possibility of simultaneous movement in a direction parallel to the direction of the deforming force. The container is installed on the base 6, in which the channel is made, where the ejector 7 is placed, made with the possibility of elastic movement in the direction of application of the deforming force, and acts as a power backwater. The friction plate 4 is installed on the working surface of the ejector 7, the friction plates 3 and 5 can be made in two ways, either as the friction plate 4 installed on the working surface of the ejector, or in contact with its side surface and moving in the direction of movement of the ejector with a speed lower, equal to or greater than the speed of movement of the ejector.

The speed of movement of the strap 4, located opposite the container wall, from the side of which additional pressure is applied, should be equal to the speed of movement of the ejector, i.e. the strip 4 is mounted on the ejector 7. In addition, the strip 4 has the ability to slide on the working surface of the ejector in a direction perpendicular to the direction of movement of the punch, namely, the direction of action of the applied additional lateral pressure moving the container wall with a speed of V ₅ .

 If the speed of movement of the strap 5 in a direction parallel to the direction applied to the working pressure is less than the speed of movement of the ejector 7, then the pressed mass of the workpiece material will flow into the gap formed between them. This, on the one hand, will lead to the achievement of the desired shape and quality of the final product.

The speed of movement of the other two friction plates 3 and 5 in the direction of the working stroke of the punch, the working planes of which are involved in the formation of the cavity to accommodate the workpiece, may be less than, equal to or greater than the speed of movement of the ejector V ₃ (speed of movement of the lower end of the workpiece).

The optimal value is considered to be the value of the speed of movement of the two side plates 3 and 5 of friction, equal to 1.3-2 the speed of movement of the ejector 7. Increasing or decreasing the speed of movement of the plates 3 and 5 of friction relative to the speed of movement of the ejector 7 does not change the qualitative picture of the work of external friction considered inappropriate. In the indicated speed range V _3.5 = (1.3 + 2) V _{4, the} external friction forces acting between the workpiece material and the friction plates from the reactive forces that impede compaction are converted into active forces that contribute to the intensive study of the outer side surface of the workpiece.

 The method is as follows.

v_п, где V_п скорость перемещения металла заготовки у верхнего торца (скорость пуансона); l_o, h_o габаритные размеры заготовки после ее подпрессовки. Скорость пуансона V_прегистрируют по скорости перемещения рабочего хода ползуна прессового оборудования.The workpiece (Fig. 1, 2) is placed in the inner working cavity formed by the strips 3, 4, 5 and the container 2. At the same time, it rests with its lower end on the plane M of the fixed base 6. On the other, upper end surface of the workpiece, set the punch 1 and pre-compaction of the workpiece material. Then an additional force is applied to the side surface of the workpiece, i.e. the container 2 is informed of the speed V _b , based on the condition that v _b

v _p , where V _{p the} speed of movement of the metal of the workpiece at the upper end (the speed of the punch); l _o , h _o overall dimensions of the workpiece after its prepress. The speed of the punch V _p recorded by the speed of movement of the stroke of the slider of the press equipment.

 At the moment when the working plane G of the bar 4 begins to move along the working surface N of the ejector 7, the power system of the latter will begin to experience the pressure exerted by the workpiece material, compressed by the forces deforming it applied to it through the punch. When there are forces on the working surface of the ejector 7 that are close to the yield strength of the workpiece material, it begins to move in the direction of the working stroke of the punch 1, while maintaining a predetermined backpressure value. The friction plate 4 resting on the working surface N of the ejector 7 has the ability to move in two mutually perpendicular directions. The first direction coincides with the direction of movement of the container, the second in the direction of the stroke of the punch. Two other, lateral levels 3 and 5 have the ability to either move only in the direction of the stroke of the punch, or in the same way as the friction plate 4 in two mutually perpendicular directions.

 For example, you can install the strips 3 and 5 freely, then they will tend to move with the speed of movement of those layers of the workpiece that will have the most intense degree of deformation (in the case of pressing a multilayer system, these will be layers whose material has the lowest bulk density), in particular lower due to superposition of shear deformations associated with the drawing of the material. You can also move the straps 3 and 5 forcibly in the speed range, namely 1.3-2 of the speed of the ejector.

 As a result of the applied force from the side of the punch 1 and the container 2, the workpiece material is extruded from the working cavity formed by the strips 3, 4, 5 and the container 2 into the working cavity of the lower base 6 parallel to the initial cavity.

 In this case, the workpiece material is compressed in the axial direction with simultaneous superposition of shear deformations in two mutually perpendicular directions. The presence of bilateral shear deformation in combination with active friction forces determines the quality study of the structure of the workpiece material and leads to a decrease in the deformation force, and consequently, a decrease in the power of the press equipment and an increase in the resistance of the deforming tool.

 At the end of the pressing process, products are removed from the working cavity of the base using the ejector 7.

 The proposed method can handle both powder and monolithic material.

PRI me R. To obtain bars from a synthetic carbide tool material, for example, grade STIM-3B / 3 measuring 30x40x80 mm, the following chemical composition was used, wt. Titanium PTM 57.6 Chrome PHIS 13.4 Carbon PM-15TS 16.6 Nichrome PH20NVO 12.4
The initial relative density of the briquettes was 50 160%; the size of the briquettes was 30x40xx160 mm. Before deformation, the preform was initiated by a heat flux formed by heating an electric spiral. The speed of propagation of the synthesis wave in the briquette was 1.4 cm / s, the burning time of the briquette was about 12 s.

v_п, и составила 31 мм/с.After the combustion was completed, a temporary pressing delay of 3.1-4.0 s was made, after which the punch began to move in the direction of the working stroke. When creating synthesis products, the deformation resistance, equal to 10 MPa, began to carry out lateral movement of the upper part of the composite container. The speed of movement of the punch V _p was 12.5 mm / s, the speed of movement of the container was calculated from the formula
v _b

v _p and amounted to 31 mm / s

When the pressure on the punch was 50 MPa, a support began to move, the speed of movement of which was V ₃ = 200-15 mm / s.

At the end of pressing the preform was removed from the apparatus and put in an oven having a temperature of 500 ^C after a two hour exposure preform was cooled in air.

After cooling, the final relative density of the samples cut from different layers of the bar was 100%. The spread in the microhardness measurements of the samples did not exceed 1%, which indicates a uniform study of the structure. The study of the microstructure showed a uniform distribution of physico-mechanical properties throughout the volume of the bar. Physico-mechanical properties of the bar were: Density, g / cm ³ 5.6 Hardness, HRA 95
Bending strength, kgf / mm ² 120
Impact strength, kgf m / cm ² 0.15
Physico-mechanical characteristics of the obtained product are increased by more than 2%. The level of mechanical properties is fully consistent with the set. The resulting products were used as regular bars and knives for cutting sheet material from stainless steel and foil of light non-ferrous metals, and also as cutting inserts when machining extra strong metals such as EI954. The resistance of knives is 10 times higher than the resistance of known tungsten-containing hard alloys V15K6, VK-6.

Claims (1)

METHOD OF PROCESSING MATERIALS BY PRESSURE, which consists in applying the main deforming force to the upper end of the workpiece, an additional force perpendicular to the main one, on the side surface of the workpiece with subsequent extrusion of the workpiece material into the tool channels, characterized in that, in order to improve the quality of the resulting products by increasing uniformity properties of the material along their length, the extrusion of the material is carried out in a direction parallel to the direction of application of the main deforming force, p and this movement of the workpiece material in the region of its lower end to produce a rate v determined from the dependence _of

where v _{s the} speed of movement of the material at the lower end of the workpiece, m / s;
v _{p the} speed of movement of the material at the upper end of the workpiece, m / s;
ρ _o , ρ _to, respectively, the relative initial and final density of the workpiece material, kg / m ³ ;
λ the degree of drawing, determined from the condition

where l _{0 is the} initial width of the workpiece, mm;
l _{1 the} current width of the undeformed part of the workpiece for a fixed period of time, mm

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