RU2288803C1 - Method for forging ingots in forging apparatus with four strikers - Google Patents

Abstract

FIELD: plastic working of metals, namely ingot forging in presses of four-striker forging systems.

SUBSTANCE: method comprises steps of squeezing ingot by means of four strikers for forming four dents on lateral surface of ingot; squeezing said dents, feeding and tilting blank, sizing forged piece. Said dents are squeezed for forming octahedral cross section blank having width values of faces formed at squeezing process no less than width values of non-squeezed faces. Blank is subjected to tilting after each pass alternatively by angle 45° and 135° in the same circumference direction. Before sizing, blank is tilted by angle multiple to angle 22.5°.

EFFECT: less loss of yield for forged pieces after their mechanical working.

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Description

The invention relates to the processing of metals by pressure, and in particular to methods of forging ingots on presses in four-forging forging devices.

The invention can be used in the engineering and metallurgical industries in the production of forgings of various cross-sections from carbon and alloy steels, as well as from special alloys on hydraulic forging presses equipped with four-side forging devices.

A known method of forging workpieces on four-radial forging machines, including multi-pass drawing of the workpiece with a pitch of it between passes at 45 °, forming in one of the passages on the side surface of the workpiece four protrusions evenly spaced along its perimeter, which are crimped in subsequent passes with the simultaneous formation of similar protrusions. In this case, the protrusions are molded with the ratio of their height to their width not exceeding 1.5, and with the ratio of the width of the cavity between the protrusions to their height not less than 1.1 [1].

This method allows to obtain high quality forgings due to intensive deformation study of the metal structure.

The disadvantage of this method is the possibility of clamps on the surface of the forgings in the process of deformation of the protrusions, which leads to the need to increase the allowance for machining and reduce the yield of metal.

There is also a method of forging workpieces on a four-gage radial forging machine, comprising crimping the workpiece along its entire length with strikers with lead-in and gauging sections until uniform projections are formed on its side surface with feeds, workpiece tilts by 45 ° and subsequent crimps of formed protrusions, as well as forgings calibration [2].

A disadvantage of the known forging method is the possibility of the appearance of chokes and clamps on the surface of the forging during the forging process, which leads to an increase in machining allowance and, consequently, to a decrease in the yield of metal. In addition, when forged in a known manner, the forgings are not calibrated effectively enough, which also leads to a decrease in metal yield during subsequent machining.

The objective of the invention is to develop a method of forging an ingot in a four-sided forging device, which provides an increase in the yield of metal on the forgings after their machining.

The problem is achieved in that in the method of forging ingots in a four-sided forging device, including the compression of the ingot by four strikers with the formation of four protrusions on its striking surface, crimping these protrusions, feeding and tilting the workpiece, as well as calibrating the forging, it is new that the protrusions compress to obtain a blank of an octagonal cross-section with a width of faces formed during the compression process not less than the width of the free faces, while the blank is turned over after each pass alternately at an angle of 45 and 135 ° in a circumferential direction, and the workpiece before calibration turn over an angle multiple angle 22.5 °.

Figure 1 presents the compression scheme of the ingot of circular cross section in a four-side forging device with the formation of four protrusions; figure 2 - diagram of the compression of the four protrusions after turning the ingot, shown in figure 1, at an angle of 45 °; figure 3 is a diagram of the compression of the cross section of the workpiece shown in figure 2, after its tilting angle of 135 °; figure 4 - diagram of the compression of the workpiece octagonal cross-section after tilting it to an angle of 22.5 ° or a multiple of this angle. 1 - cross section of the ingot, 2-5 - dies, 6, 7 - cross sections of the workpiece after the first and second passes, respectively. Arrows indicate the direction of rotation of the workpiece.

Patented forging method in a four-sided forging device is as follows.

The ingot 1 heated to the forging temperature is taken out of the heating furnace and, using the manipulator, is fed into the working area of the press, where it is forged in the four-head forging device by the strikers 2-5 (Fig. 1). In the forging process, four strikers 2-5 are introduced into the body of the ingot 1, forming four projections between the strikers. After the end of the passage, the workpiece is turned over at an angle of 45 °, and then the tabs are crimped (figure 2). When crimping the protrusions, a blank of an octagonal cross-section is formed 6. The width of the faces "mn" formed during the compression should be at least the width of the free faces "nf", i.e. not crimped on this passage (figure 2). Obtaining an intermediate blank of such an octagonal cross-section allows crimping in the next pass without clamps on its surface. Before the next pass, the workpiece 6 is turned over in the same circumferential direction as with the previous tilting, but already at an angle of 135 °, and its edges are squeezed, obtaining a workpiece of an octagonal cross section 7 (Fig. 3). If you still want to reduce the cross-section of the workpiece, then it is edged at an angle of 45 ° in the same circumferential direction and crimped along the edges (not shown in the drawings). The final design of the round cross-section of the forgings is made in the last passes, during its calibration. In this case, the preform is calibrated over an angle that is a multiple of the angle of 22.5 °, and crimped along the ribs (Fig. 4). With successive tilting (in the aisles) of the workpiece at angles of 45 ° and 135 °, as well as tilting it before calibration by an angle multiple of 22.5 °, uniform working of the cast metal structure over the entire cross section is ensured without forging defects on the forging surface. When tilting the workpiece before it is calibrated to an angle that is a multiple of the angle of 22.5 °, crimping is carried out along the ribs, which leads to an increase in the number of faces of the workpiece and brings its cross section closer to round. Further calibration of such a workpiece with flat or notched strikers provides forgings of circular cross section as close as possible to the geometric circle.

Example. An ingot with a diameter of 750 mm from steel 40XMA was heated to a temperature of 1200 ° C in a gas chamber furnace and forged on a hydraulic forging press with a force of 20.0 MN in a four-side forging device for forging with a diameter of 350 mm. After billing, the ingot was crimped by four strikers in a four-flange forging device to a size of 540 mm with the formation of four protrusions on its side surface. Then, the blank was turned over at an angle of 45 ° and squeezed out these protrusions to a size of 480 mm. The resulting workpiece was edged at an angle of 135 ° in the same circumferential direction and crimped to a size of 400 mm. After that, the workpiece was edged at an angle of 45 ° and squeezed it also to a size of 400 mm. The resulting preform was edged at an angle of 135 ° and crimped to a size of 350 mm, and then edged at an angle of 45 ° and also forged to a size of 350 mm. All tilting blanks were made in one circumferential direction. A billet of an octagonal cross section with dimensions of 350 mm was edged at an angle of 22.5 ° and forged to a size of 350 mm, after which the resulting billet was calibrated with four flat dies in a four-billet forging device to obtain a forging with a diameter of 350 mm. In the calibration process, the blank after each crimping was tilted at an angle of 10 °. After annealing and dressing, the actual dimensions of the cross section of the forgings were - diameter 350 ⁺² mm There were no clamps, nicks and other defects on the forging surface, which allowed it to be pierced through a diameter of 340 mm without areas of blackness. The yield of metal (from ingot to turned forging) was 76.2%.

For comparison, according to the method adopted as a prototype, the same 40XMA steel ingot was forged for forging with a diameter of 350 ⁺⁵ mm. On the surface of the forgings were shackles. Therefore, to obtain a suitable forging, it was machined through a diameter of 320 mm. The yield of metal (from ingot to turned forging) was 65.4%.

Thus, the patented forging method allows to increase the yield of metal by 10.8%.

INFORMATION SOURCES

1. USSR author's certificate No. 1003983, MKI B 21 J 1/04, 1981

2. USSR author's certificate No. 1570829, MKI B 21 J 1/04, 1989

Claims (1)

A method of forging ingots in a four-sided forging device, comprising crimping an ingot with four strikers with forming four protrusions on its side surface, crimping these protrusions, feeding and tilting the workpiece, and calibrating the forging, characterized in that the protrusions are crimped to produce an octagonal cross-section with a width of formed in the process of crimping the faces not less than the width of the free faces, while the workpiece is turned over after each pass alternately at an angle of 45 ° and 135 ° in one circumferential direction, and before by libration, the workpiece is turned over at an angle that is a multiple of the angle of 22.5 °.

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