SU770635A1 - Method of producing variable section articles by hydroextrusion - Google Patents

Description

(54) METHOD FOR OBTAINING VARIABLE SECTION PRODUCTS BY HYDROEXTRADING

one

This invention relates to the treatment of materials with high hydrostatic pressure. It can be used in engineering and metalworking. The most effective is its use in the manufacture of hollow products with external and internal sizes varying in length.

Existing manufacturing technology for such parts provides for machining of a stamped billet and is characterized by high labor intensity and low metal utilization. The use of a high pressure fluid permits the manufacture of parts of variable cross section using cold plastic deformation. For example, methods 1 and 2 for the manufacture of pipes of variable cross section are known, including the slump of a hollow billet with its simultaneous distribution by high-pressure liquid. The disadvantages of the methods:

-the need for complex equipment (special press with two m. sliders);

- reduced plasticity of the material during shaping;

- limited product range (only hollow products).

The closest to the proposed method is the hydroextrusion of variable-section products from a bar, which means that the billet is placed in a matrix and deformed with a high-pressure fluid, then the pressure is reduced to atmospheric, the billet is rotated and the other end is extruded.

-low process performance;

- limited nomenclature of parts 10 (only from bars).

The aim of the invention is to increase the production of the process and the expansion of the product range.

This goal is achieved by placing one blank with one end in the matrix on the free end of the blank and placing another, deaf, matrix, applying an axial force to the latter to ensure the occurrence of contact stresses on the ends of the blank with a value of not less than 0.05 20 material yield strength the subsequent hydroextrusion of the preform is carried out in two matrices simultaneously.

FIG. 1 shows an apparatus for carrying out the method at the time of filling.

liquid container, incision; in fig. 2 - the same, at the time of the end of the process of shaping; in fig. 3 - diagram of the forces acting on the deaf matrix and the workpiece. The device for carrying out the method consists of a plunger 1 with seals, a container 2, a nut 3, a stem 4, a spring 5, a blank matrix 6 with longitudinal grooves for the passage of fluid, a workpiece 7, a sleeve 8 and a lower matrix 9. The container 2 is fastened with stand 10 pin and set on the press table. The plunger 1 is attached to the press slide. In the initial position, the plunger 1 occupies the uppermost position, and the die 6 is pushed out of the container 2 with the help of a pin 4. At the same time, the spring 5 is released. The workpiece 7 is installed in the matrix 9 and centered on its conical surface.

When the plunger 1 is lowered, the die 6 is placed on the upper end of the workpiece 7 and pressed against the workpiece face by the force of the spring 5. The mutual position of the device parts at this moment is shown in FIG. one.

In this position, liquid is poured into the container 2 through its radial opening, then the press is turned on. The plunger moves downward, while the pressure of the fluid in the container appears. The plunger stroke to create the required fluid pressure is less than the spring stroke until the turns come into contact. Under the action of the force of the spring 5, stresses are created on the contact surfaces of the workpiece and the dies. As the brush moves, the fluid pressure rises and at some point reaches the P-t 6i value. Since (- P, the penetration of fluid into the cavity of the matrix 6 is stopped. An uncompensated area is formed, whereby the matrix 6 is pressed against the workpiece 7.

The force S 1, acting on the upper end of the matrix 6 at the pressure of the fluid P i, is expressed as:

S, f Di .Pt,

where D 1 - the outer diameter of the deaf matrix.

The force S 5 acting on the lower end of the matrix 6 at a pressure P i will be expressed as:

S., f () .Р ,, where Dn is the diameter of the workpiece.

The force that presses the matrix 6 to the workpiece 7 when the pressure of the fluid P i is expressed as the difference:

S ,,;

The voltage G on the contact surface when the pressure of the fluid P i is expressed as the sum (jt + G,

NW-- ICjDi -.

FK-.g 1,

where the contact surface is the workpiece. Thus, the voltages on the contact surface greatly exceed the magnitude of the fluid pressure, thereby preventing the latter from penetrating into the cavity of the matrix. As the pressure increases, the magnitude of the contact stresses increases, as a result of which the plastic deformation of the workpiece begins, the sediment of which is eliminated due to the lateral support of the liquid.

FIG. Figure 2 shows the moment of the end of the process of shaping when the pressure of the fluid P is 2. Since the degree of compression of the workpiece in the matrix 6 is greater than in the matrix 9, the initial workpiece 7 is deformed into the matrix 9, then (after resting in its bottom) at the pressure necessary to form in the upper die 6, it will begin to move relative to the workpiece 7. At the time the die 6 contacts the sleeve (abutment) 8, the process ends, and a gap is necessary between the inner end surface of the die 6 and the upper end of the part.

When the plunger 1 moves upward, the article 11 moves with the die 6 and is removed from the container. The removal of the product 11 from the matrix 6 is carried out with the press moving upwards with a special device (not shown in the fig.).

The product with the stroke upwards remains in the upper section due to the fact that the friction force on the surface in the matrix point 6 is constructively higher (due to the longer length of the matrix point).

Thus, the proposed method of hydro-extrusion allows the manufacture of flat and hollow products of variable cross-section in one pressure generation cycle.

In the laboratory of hydroextrusion of the IPM UNPAN USSR, the proposed method was implemented using steel pipes (Dj 66 mm, O., 54 mm). They were formulated into products with Dy 50 .mm, DBH- 39 mm at one end and 54 mm and D 2vn 39 mm at the other end, while

0 the size of the product in the middle remained equal to the size of the workpiece. The total length of the product was 610 mm. The fluid pressure during shaping to the specified dimensions was 3 kbar. Experiments on model samples and blanks of large size showed that reliable compaction of the workpiece in both matrices occurs at contact stresses of at least 0.05 (Gd of the workpiece material, where ffg is the yield strength of the material.

JJ The creation of an axial force of pressing a dead matrix to the workpiece was carried out with the help of a spring and showed the effectiveness of this method of creating a pre-compaction.

The application of the proposed method provides in comparison with existing the following advantages:

—inflation of the productivity of the process by about 2 times due to a decrease in the number of operations during machining;

- reduction of metal consumption by about 2-2.5 times.

-improving the mechanical properties of products.

Claims (3)

1. Drink X. Mechanical properties of materials under high pressure. “Peace, 1973, p. 231-233. 2. USSR author's certificate for application number 2524723/27, cl. At 21 J 5/04, 11.05.78. 3. Drink X. Mechanical properties of materials under high pressure, Part 2, “World, 1973, p. 103 (prototype). T 6,6 Р 1кг / с „г