RU2362647C2 - Method for production of hollow forged pieces - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to metal working and may be used to manufacture hollow forged pieces in hydraulic forging presses. Hollow billet is heated, pressed by manipulator at one end and supplied to working zone of four-striker forging device of hydraulic forging press. Hollow billet is forged. Every single drafting is carried out with deformation degree of 2-15%. After every drafting the billet is tilted. Prior to clamping of hollow billet, a technological insert may be installed at its end with diametre equal to internal diametre of hollow billet.

EFFECT: simplification of hollow forged pieces manufacturing process and possibility to use thin-walled billets.

3 cl, 2 dwg, 1 ex

Description

The invention relates to the processing of metals by pressure, and in particular to methods for manufacturing hollow forgings on hydraulic forging presses.

The invention can be used in the engineering and metallurgical industries in the production of hollow forgings from hollow billets on hydraulic forging presses equipped with four-side forging devices.

A known method of manufacturing a hollow forgings, including obtaining a hollow billet, heating and subsequent compression of it from four sides on a radial forging machine (RCM) with feeds and tilts [1].

This method allows to obtain accurate hollow forgings with constant and variable cross-section along the length of the forging. However, the disadvantage of this method is that for its implementation requires special radial forging machines, which are unique and expensive equipment.

There is also a method of manufacturing large hollow forgings from alloy steels, including the manufacture of a hollow ingot-billet, the manufacture of a plastic technological insert, heating the workpiece, installing the insert in the cavity of the workpiece, plastic deformation by forging on a hydraulic forging press of a hollow workpiece with an insert and subsequent removal of the insert [2] .

The known method allows to obtain hollow forgings from alloy steels with high quality metal.

The disadvantages of this method are the impossibility of forging hollow forgings from forging with a thin wall without forging on the forging press without a plastic technological insert deformable together with the workpiece (δ / d≤0.1, where δ is the thickness of the workpiece wall, d is the outer diameter of the workpiece), and also the complexity of the process, because the removal of the deformed insert and selection of the material of this insert is required. The basis of the invention is the task: by using a four-flange forging device that allows plastically deforming a hollow billet from four sides, and using regulated deformation modes, to provide a simplification of the process and the possibility of manufacturing hollow forgings from thin-walled blanks.

The problem is achieved in that in the method of manufacturing hollow forgings, including obtaining a hollow billet, heating it, clamping and holding the billet from one end with a manipulator, and subsequent plastic deformation by forging on a hydraulic forging press with feeds and taps, the new is that plastic deformation forging is carried out in a four-sided forging device with a degree of deformation with each unit compression of 2-15%.

The task is also achieved by the fact that before clamping the hollow billet with a manipulator, a technological insert is installed at its end, the diameter of which is equal to the inner diameter of the hollow billet.

The task is also achieved by the fact that the hollow billet is obtained from a seamless pipe.

Figure 1, 2 presents a diagram of the retention of the hollow billet with the jaws of the manipulator, where 1 is the hollow billet, 2 is the technological insert, 3 is the jaw of the manipulator.

The patented method is as follows.

A hollow billet heated to forging temperature, for example, a pipe, is clamped at one end by the jaws of the manipulator and fed into the working area of the forging press, where a four-sided forging device is pre-installed [3]. Using a press, the four-sided forging device is opened, a hollow billet is fed to its strikers and its plastic deformation is forged. In the forging process, the hollow billet is simultaneously crimped from four sides, and between the crimps the billet is fed and tilted. In this case, single compression of the hollow billet in a four-sided forging device is carried out with a degree of deformation of 2-15%.

For reductions with a degree of deformation of less than 2%, the forging process significantly lengthens, the temperature of the workpiece can significantly decrease, which will require additional heating.

When crimping with a degree of deformation of more than 15%, clamps may appear on the workpiece, which will lead to its marriage.

When clamping a thin-walled hollow workpiece with the jaws of the manipulator, significant distortion of its geometry is possible. Therefore, before clamping a thin-walled tubular billet with the jaws of the manipulator, a technological insert is installed at its end, the diameter of which is equal to the inner diameter of the hollow billet (Figs. 1, 2).

A hollow billet can also be obtained from a seamless pipe, if the dimensions of this pipe are suitable.

After forging, the resulting hollow forging is, if necessary, subjected to heat treatment.

Example.

A hollow billet with an outer diameter of 425 mm made of steel 17G1S made of a seamless pipe with a wall thickness of 20 mm was heated in a gas chamber furnace to a temperature of 1150 ° C for 40 minutes. Then the heated billet was taken out of the furnace and a technological insert made of steel 20 was installed on the side of one of its ends, the diameter of which was equal to the inner diameter of the hollow billet, i.e. diameter 405 mm. The manipulator sponges clamped the technological insert protruding from the workpiece and fed the workpiece to a hydraulic forging press with a force of 20MN. Previously, a four-side forging device was installed in the working area of the press. They turned on the press and began to feed the hollow billet into the working area of the forging device with the manipulator. Each single compression of the hollow billet was carried out with a degree of deformation: 5.9% in the first pass; 5% - on the second pass; 5.3% - on the third pass; 5.6% on the fourth pass and 2.9% on the fifth pass. After each crimping, the workpiece was tilted at an angle of 15–20 °, and the feed was carried out at 120–140 mm. From the side opposite to the manipulator, the workpiece was forged on a forging with an outer diameter of 330 mm with a tolerance of ± 1.5 mm. Then, the technological insert was removed from the obtained forgings. The forging obtained after such plastic deformation had a circle geometry in cross section, and its surface was smooth, without clamps and cracks.

Thus, the patented method for manufacturing hollow forgings provides hollow forgings from thin-walled blanks without the use of a plastic technological mandrel deformable with the blank, and simplifies the process.

INFORMATION SOURCES

1. Rostovschikov V.A. Production of steel pipes on radial forging machines company GFM // Sat. tr International conference "Ferrous metallurgy of Russia and the CIS countries in the XXI century." M., 1994, v. 4, pp. 99-101.

2. USSR author's certificate No. 1559538, MKI B21J 5/00, 1989

3. RF patent No. 2242322 dated April 16, 2003, MKI B21J 13/02, 7/16.

Claims (3)

1. A method of manufacturing a hollow forgings, including obtaining a hollow billet, heating it, clamping and holding it from one end with a manipulator, and then obtaining plastic deformations in the hollow billet by forging it on a hydraulic forging press with feeds and tilts of the hollow billet, characterized in that the forging is carried out in a four-side forging device with a degree of deformation with each single compression of 2-15%. 2. The method according to claim 1, characterized in that before the clamping of the hollow billet with a manipulator, a technological insert is installed at its end, the diameter of which is equal to the inner diameter of the hollow billet. 3. The method according to claim 1, characterized in that the hollow billet is obtained from a seamless pipe.

Images