RU2535831C1 - Hollow channel pressing method, and device for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: pressing of hollow channels is performed in a device that includes a container, a puncheon, a die with an alignment shell, a pressure plate with a through hole and a pressure needle with a conical section. The puncheon has a blind hole, in which a shock-absorbing device connected to the pressure needle is fixed. The pressure needle is moved along the pressing axis of the puncheon and the pressure plate. The latter is provided with a cavity corresponding as to a shape to a pressure needle section with maximum diameter. After a workpiece is installed into the container, and the pressure needle is introduced into it and aligned, the pressure needle is moved till its conical section contacts the end surface of the workpiece. Then, the pressure needle is moved inside the puncheon to the side opposite to pressing direction. After an extrusion discard is formed, movement of the puncheon is stopped, and the pressure needle is moved in the pressing direction. Forcing-through of the extrusion discard is performed into the die hole with a conical section of the pressure needle.

EFFECT: complete pressing of a hollow channel without any formation of an extrusion discard.

3 cl, 4 dwg

Description

The invention relates to the field of metal forming, in particular to the production of hollow profiles by extrusion, and can be used in the production of pipes from special steels and alloys, as well as non-ferrous metals and their alloys.

A known method of pressing pipes from high-strength alloyed alloys, including feeding a heated sleeve with technological lubricant to the press container, installing a die with a grease washer on it, inserting a needle into the sleeve and extruding a metal with a metal stamp into the die hole. After taking the press stamp, needle and container back with a saw, cut off the press residue from the pipe, which together with the press washer is pushed into a special tray (Gulyaev G.I. et al. Pressing steel pipes and profiles. - M .: Metallurgy, 1973 , p. 70).

The disadvantages of this method are the formation of press residue and reduced yield, as well as an increase in the complexity of the process due to the removal of the press residue.

The closest technical solution adopted for the prototype is a method of pressing pipes, including heating the technological washer to a regulated temperature below the heating temperature of the workpiece, feeding the washer to the needle, feeding the workpiece to the pressing axis, pressing the pipe, removing the press residue from the container and using it in as the back technological washer during subsequent pressing (RF patent No. 2184633, B21C 23/08, published on July 10, 2002).

The disadvantage of this method is the increased consumption of metal due to the formation of a press residue in the container and reduced yield.

A device for pressing hollow profiles containing a container, a matrix with a centering sleeve, a press stamp with a press washer and a needle located on the container, on the working part of which an additional centering sleeve is placed in contact with the workpiece, is known. The surfaces of the bushings in contact with the workpiece are tapered, and the centering bushings themselves are made of the workpiece material (AS USSR No. 252272, B21C 25/04, publ. 09/22/1969).

The disadvantage of this device is the one-time use of centering sleeves, for only one product, which increases the consumption of metal and increases the cost of manufacturing centering sleeves. In addition, when pressing the workpiece in the container, the shape of the centering sleeves changes, which leads to a displacement of the press needle and an increase in the difference in the product.

The closest technical solution adopted for the prototype is a device for pressing hollow profiles containing a container, a stamp, a die, a needle, equipped with a centering element in the form of a tube, the outer surface of which is in contact with the working walls (inner surface) of the matrix, while centering the element is made of mild steel. When pressing the workpiece in the container, the needle is rigidly fixed at one end in the hole of the press washer. The working end of the needle through the centering element is included in the point of the matrix, which allows you to extrude the workpiece in the container without violating the alignment of the needle (RF patent No. 2314887, B21C 25/00, publ. 20.01.2008).

The disadvantage of the prototype in addition to the complexity of installing the centering element in the hole of the matrix is the need for additional pressing forces in the initial stage of the process required to push the centering element from the hole of the matrix. In addition, this device does not provide complete extrusion of the press residue from the matrix, which leads to an increase in metal consumption.

The technical problem solved by the inventions is the complete extrusion of a hollow profile without the formation of a press residue and increase the yield coefficient during pressing.

The problem is solved due to the fact that in the method of pressing hollow profiles, including the installation of the matrix, feeding into the press container a workpiece with an axial hole, introducing into the workpiece a press needle made with a conical section, centering, moving and extruding the workpiece metal into the hole with a punch matrices to the formation of a press residue, according to the invention, after centering, the press needle is moved until its conical section comes into contact with the end surface of the workpiece, then the pre with needle-punch in a direction opposite to the pressing direction, after the formation of the discard is stopped and the movement of the punch press is moved within the needle-punch and press washers in the pressing direction, the conical portion prodavlivaya press residue at the die aperture.

The problem is also solved due to the fact that in the device for pressing hollow profiles containing a container, a punch, a die equipped with a centering cup, a press washer with a through hole, a press needle made with a conical section, the working end of which is placed in the centering cup , according to the invention, a blind hole is made inside the punch coaxially to the pressing axis, in which a shock-absorbing device is rigidly fixed, connected to the other end of the press needle, while the press needle is made with the possibility of emescheniya along the pressing axis within the punch and the press washer, and a press washer further configured recess shaped portion corresponding to a press with a maximum diameter of the needle. In addition, the shock-absorbing device is made in the form of a compression spring.

The execution inside the punch coaxial to the axis of pressing a blind hole provides the possibility of rigid fastening in it a shock-absorbing device, which is connected to the end of the press needle. In this case, the press needle is arranged to move along the axis of pressing inside the punch and press washer, which allows the press needle to change its position relative to the press washer and punch as the volume of metal in the container changes.

The shock absorbing device accumulates the kinetic energy of the workpiece as the press washer moves in the pressing direction. So, moving the press needle in the direction of pressing, after the contact of its conical section with the end surface of the workpiece, the press needle is moved inside the punch and the press washer in the direction opposite to the pressing direction. In this case, the press needle transfers the kinetic energy of the workpiece to the shock-absorbing device, which, in turn, accumulates it until the press residue is formed. After the formation of the press residue, the movement of the punch is stopped. At this time, the hollow profile extends the press residue into the die hole, and the press needle is moved inside the punch and press washers in the pressing direction due to the accumulated force of the shock absorber. As a result, the press needle presses the press residue through the conical portion into the hole of the matrix, and a finished hollow profile is obtained.

The invention is illustrated by drawings, where Fig. 1 schematically shows a sectional view of a pressing device, in particular centering a press needle, Fig. 2 shows a device during a pressing process, Fig. 3 shows a device at the initial moment of pressing out a press residue, in Fig. .4 shows the device upon receipt of the finished hollow profile.

A device for pressing hollow profiles (Fig. 1) contains a container 1 with an inner sleeve, a matrix 2 in which a centering cup 3 is placed, a punch 4 with a press washer 5 located at the end, a press needle 6 made with a conical section, a working end which is located in the centering cup 3. Inside the blind hole of the punch coaxially to the pressing axis, a shock-absorbing device is fixed 7. The press needle 6 is arranged to move along the pressing axis inside the punch 4 and in the hole of the press washer 5.

The method of pressing hollow profiles is implemented using the device as follows. On one side of the container 1, a matrix 2 is installed in the matrix holder, in which a centering cup 3 is placed. After that, a grease washer is installed. Then the workpiece 8 (if necessary heated to a predetermined temperature) with an axial hole is fed into the container 1, a punch 4 is inserted into the container, at the end of which a press washer 5. The working end of the press needle 6 is fixed in the centering cup 3, while the other end the needle is located in the press washer 5 and the punch with the possibility of movement along the axis of pressing and inside the punch 4 and is connected to the shock-absorbing device 7. The press washer 5 is additionally made with a recess corresponding in shape to the section of the press needle with a maximum diameter D and providing a set portion inside it press the needle.

The punch 4 (figure 2) transfers the pressure of the press to the press washer 5 and the workpiece 8 and causes the metal to flow out into the hole of the die 2. In this case, the pressure of the workpiece metal on the conical section of the press needle 6 moves the press needle in the direction opposite to the pressing direction, and a shock-absorbing device made, for example, in the form of a compression spring 7 of height H ₀ is compressed to H ₁ , which allows the press needle to go into the recess of the press washer. The pressing process is continued until the formation of the expected press residue 9 in the container 1 (Fig. 3), after which the movement of the punch 4 is stopped. Then, the hollow profile 10, due to the action of inertia forces, begins to stretch the press residue 9 into the hole of the matrix 2 (Fig. 4) ) At the same time, when the volume of metal in the container decreases and the forces act on the conical section of the press needle, the shock-absorbing device, made for example in the form of a compression spring 7, is unclenched, and due to the additional force from the accumulated kinetic energy, the press needle 6 pushes the remainder through the conical section 9 into the calibrating section of the matrix 2, which contributes to obtaining a finished hollow profile 10.

To implement the proposed method, the following conditions must be met:

$$W_{\mathrm{to}}^{PR.\mathrm{about}\mathrm{from}t.}<W_{\mathrm{to}}^{PR\mathrm{at}\mathrm{well}.}\le W_{\mathrm{to}}^{s\mathrm{but}g.},(\mathrm{one})$$

- кинетическая энергия пресс-остатка, Дж;Where $$W_{\mathrm{to}}^{PR.\mathrm{about}\mathrm{from}t.}$$

- kinetic energy of the press residue, J;

- кинетическая энергия пружины сжатия, Дж; $$W_{\mathrm{to}}^{PR\mathrm{at}\mathrm{well}.}$$

- kinetic energy of the compression spring, J;

- кинетическая энергия заготовки, Дж. $$W_{\mathrm{to}}^{s\mathrm{but}g.}$$

- kinetic energy of the workpiece, J.

The maximum force P required for extruding the workpiece metal from the container using a press needle with a conical section can be determined by the following relationship:

$$P=\frac{N_f}{{\nu }_P}+\frac{\pi }{\sqrt{3}}{\sigma }_S(\frac{\mathrm{one}}{\mathrm{four}}C+\mu B),(2)$$

where N _f - power shaping, W;

ν _P - pressing speed, mm / s;

µ is the drawing ratio;

σ _S is the resistance of the metal to plastic deformation, MPa;

B and C are the variable parameters of the corresponding dependencies for determining the power of contact friction forces and the power developed by the maximum tangential stresses on the surfaces of velocity discontinuities in the workpiece, the definition of which is presented in (Vydrin A.V. Mathematical modeling of the process of pressing pipes of variable section / A.V. Vydrin, I.Yu. Pyshmintsev, Y.I. Kosmatsky // Steel. Production of pipes. - 2013. - Issue 2. - S.39-41). To determine the geometrical parameters of the spring and the force that the compressed spring must provide when unclenched, the value of the spring index will be determined from the reference tables (Birger I.A. et al. Strength analysis of machine parts: Handbook. - M.: Mechanical Engineering, 1993, p. 170, table 4). The implementation of the inventive device for implementing the method of pressing hollow profiles with a shock absorber located inside the punch, made, in particular, in the form of a compression spring, allows to reduce the pressing force at the stage of pressing out the material of the hollow profile and increase the yield coefficient.

The method of pressing hollow profiles was tested on a vertical hydraulic test press PMM-125 with a force of 1.25 MN. The implementation of the proposed method and device required a change in the design of the pressing tool and retrofitting of the press with special devices. A punch with an outer diameter of 50 mm is made with a blind hole with a diameter of 13.0 mm coaxial to the pressing axis, in which, for example, a compression spring with a height of 40.0 mm is fixed at one end, the average diameter of the spring is 12.0 mm, the diameter of the wire cross section is 1 , 4 mm. The outer diameter of the press washer is 58.0 mm, the diameter of the through axial hole is 13.0 mm, the diameter of the recess in the press washer corresponds in shape to the portion of the press needle with a maximum diameter of 36.0 mm. The maximum diameter of the conical portion of the press needle is 35.0 mm.

A cylindrical blank of C2 grade lead with a diameter of 58 mm and a height of 100 mm with a central axial bore of 16 mm in diameter at a temperature of 25 ° C was loaded into a container with a diameter of 60 mm. A lubricating washer (in particular, from a solid grease of the Solidol type) with a diameter of 58 mm was installed in a 25 mm diameter matrix. Then, a press needle with a diameter of 12.0 mm was installed in the axial hole of the workpiece with its subsequent centering. The container was mounted on the pressing axis, and when moving the punch, the workpiece was pressed, accompanied by the simultaneous movement of the press needle in the direction opposite to the pressing direction, and subsequent pressing of the hollow profile. The speed of movement of the punch was 20 mm / s.

After fixing the maximum pressing force of 45 kN according to the indications of the inductive pressure transducer, the movement of the punch was stopped. At the same time as the punch stopped, the subsequent movement of the pipe by 5.0 mm was recorded. At this time, under the action of the compression spring, the press needle moves inside the punch and the press washer in the direction of pressing by a distance of 40 mm, forcing the remainder into the hole of the die by the conical section. The compression spring was designed to compensate for the compression force of 13.9 kN.

Thus, a pressing process was implemented with full extrusion of the workpiece material, and a hollow profile was made with an outer diameter of 25 mm, an inner diameter of 12.0 mm and a length of 670.0 mm. The mass of the pressed press residue was 0.1 kg, which provided from 3 to 5% metal savings.

Using the proposed method for pressing hollow profiles and a device for its implementation provides a complete extrusion of a hollow profile into the hole of the matrix, the absence of a press residue and an increase in the yield coefficient. The invention can be used in the manufacture of critical pipes from special steels and alloys.

Claims (3)

 1. The method of pressing hollow profiles, including the installation of a matrix with a hole on the press, feeding a workpiece with an axial hole into the press container, introducing a press needle made with a conical section into the axial hole, centering it, moving the punch and press washer and extruding it with a punch the metal of the workpiece in the hole of the matrix to the formation of a press residue, characterized in that after centering the press needle, it is moved until the conical section comes into contact with the end surface of the workpiece, then eremeschenie press the needle inside the plunger in the direction opposite to the pressing direction, after the formation of the discard stop movement of the punch and move the press the needle inside the plunger and a press washer in the direction of pressing with ensuring punching conical portion press-needle press-residue at the die aperture. 2. A device for pressing hollow profiles containing a container, a punch, a die with a hole provided with a centering cup, a press washer with a through hole, a press needle made with a conical section, the working end of which is placed in the centering cup, characterized in that the punch made with a coaxial axis of pressing a blind hole, in which a shock-absorbing device is rigidly fixed, connected to the other end of the press needle, while the press needle is made with a section having a maximum diameter and is located with the ability to move along the axis of pressing in the said holes of the punch and the press washer, in which a recess is additionally made, corresponding in shape to the portion of the press needle with a maximum diameter. 3. The device according to claim 2, characterized in that the shock-absorbing device is made in the form of a compression spring.

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