RU2247622C2 - Method for making annular forgings for bearing assemblies by free forging process - Google Patents

Abstract

FIELD: plastic metal working, namely processes for making annular forgings of bearing assemblies by free forging process.

SUBSTANCE: method comprises steps of dividing single common blank by measured ones; heating measured blanks for forging, non-completely broaching them and rolling blank around its outer diameter with use of smooth strikers; placing blank on backing plate with opening and punching core in it by means of cone punch at side of large diameter; sizing opening of forging by means of barrel-like drift; rolling out blank on mandrel and sizing it by height. Continuously cast round cross section blank is used as initial one. Local marking out of cavities in axial zone on both ends of measured blanks is performed with use of cone drift by value consisting 1/5 - 1/4 of blank height. Then measured blank is upset until leveling its end faces and forming intermediate inverse barrel relative to axis of forging.

EFFECT: lowered cost of blanks, enhanced quality of forging, decreased metal consumption of forged blanks of bearing races.

2 cl, 3 dwg

Description

The invention relates to the processing of metals by pressure, and in particular to methods of manufacturing annular forgings for bearings using free forging.

The invention can be used in the manufacture of ring forgings of bearings on a hammer or press equipment in the forging shops of machine-building and metallurgical enterprises in small-scale and mass production.

A known method of manufacturing forgings with an axial hole [1], including preliminary upsetting by flat strikers of the ingot along its height to the ratio of the diameter to the height of the forging of a larger unit (D _k / H _k > 1), an open firmware, in which the tapered underlay is installed with a pointed end on the end surface of the forging and is embedded in her body 80-90% of its height. Then the workpiece is turned over 180 °, squeezed with a draft to smooth the surface of the upper end and placed on an annular support. Next, install the underside of the conical stitching with a blunt end on the end surface of the forgings in the center and stitch through with removal of the otter. Then the ring is rolled to the required size on the mandrel with a flat top striker.

The disadvantage of this method is that the central region of the cast billet (ingot) has a defective axial zone with porosity (discontinuity) and segregation in chemical composition. During upsetting before flashing, this zone, due to uneven deformation along the height of the forging, propagates into its body and, during subsequent flashing, is not completely removed, forming defective metal regions on the inner surface of the annular forging. To remove the defective metal in this case, it is necessary to increase the allowance for machining, which reduces the yield and increases the intensity of the manufacture of forgings.

Closest to the proposed method according to the technical essence is a method for producing annular forgings for bearings [2] (Fig. 1). It consists in the fact that a round pre-deformed common workpiece is divided into measured workpieces taking into account the required size along the length. Next, the measured billets are heated for forging and are deposited in a predetermined size in diameter on flat strikers to the required thickness (Fig. 1,). Then the incomplete forging of the forging is made by basting the cavity with a conical piercing from the side of its small diameter. Then the forgings are turned over 90 ° and run on its outer diameter using flat strikers. Next, the forging is turned over 90 °, installed on a backing plate with a hole and the core is stitched with a conical piercing from the side of its larger diameter. Subsequently, the forgings are calibrated by barrel-shaped or cylindrical piercing, and then they are rolled out by free forging on the mandrel with flat dies or on a rolling machine and calibrated by height.

The disadvantage of this method is that it cannot be used continuously cast billet of circular cross section with its inherent zone of axial porosity (discontinuity). When using a continuously cast billet for this method, incomplete removal of poor-quality (porous) metal from the middle of the forging occurs, as a result of which it rolls onto the inner contact surface of the treadmill of the outer bearing ring with its rolling body. To eliminate this drawback, it is necessary to increase the metal consumption for stock to remove the defective metal.

The technical problem solved by the invention is to reduce the cost of billets, improve the quality of forgings, save metal and reduce the metal consumption of forged billets of bearing rings, expand the range of sizes of forgings of bearing rings obtained from continuously cast billets with free forging.

The problem is solved by using a continuously cast round billet, which is divided into measured billets, as the initial one, and from the two ends of the measured billets obtained as a result of cutting a continuously cast billet, they locally mark the cavities in the axial zone with conical piercing by the amount up to 1 / 5-1 / 4 of the height of the workpiece. After that, the measured workpiece is deposited as a whole until the end surfaces are aligned with the formation of an intermediate return barrel relative to the forging axis. As a result, the central porosity zone of the NLZ is localized near the axial zone of the forging without propagating to peripheral regions relative to the axis of the forging. Then the workpiece is forged to the required dimensions in height and diameter using standard technology, followed by cutting the central part, calibrating the hole with a cylindrical piercing and rolling ring forging obtained by forging on the mandrel with a flat upper striker or on a rolling machine.

In addition, in order to expand the standard sizes of bearing rings obtained by free forging from a continuously cast billet, and to reduce the dimensions of the axial discontinuity zone of a continuously cast billet for its subsequent removal when flashing, before cutting a continuously cast billet into measured billets, forging is carried out by a continuously cast billet forging with feeding to the length of the striker, using a half-circular undercut, mounted on the workpiece along its longitudinal axis under the upper striker. The broach is carried out according to the scheme:

- pushing the acceleration into the body of the workpiece;

- canting of continuously cast billets along the longitudinal axis by 180 °;

- pushing the acceleration into the body of the workpiece;

- tilting of continuously cast billet by 90 °;

- pushing the acceleration into the body of the workpiece;

- tilting of continuously cast billet 180 °;

- pushing the acceleration into the body of the workpiece;

- forging by broaching on flat strikers for a given diameter.

The invention is illustrated by drawings, which show:

figure 1 - a known method of forging annular forgings from a deformed billet of circular cross section.

figure 2 - the proposed method of forging ring forgings from continuously cast billets of circular cross section according to claim 1.

figure 3 - the proposed method of forging ring forgings from continuously cast billets of circular cross section according to claim 2.

Figure 1 schematically depicts the steps of the manufacturing process of annular forgings for bearings by free forging, in the manufacture of forgings in a known manner.

Upper hammer 1, dimensional blank 2, axial discontinuity zone 3, lower hammer 4, forging 5, conical 6 pier, extension 7, lining ring 8, otter 9, calibration 10 piercing, mandrel 11, rolling ring 12, mandrel support for rolling 13.

This method is implemented as follows: a round pre-deformed common workpiece is divided into measured blanks 2, taking into account the required size along the length. Next, the measured workpiece 2 is heated for forging and are deposited in a predetermined size in diameter on the flat strikers 1 and 4 to the desired thickness (Fig. 1, steps 1 and 2). Then the incomplete forging of the forgings is done with a conical piercing 6 from the side of its small diameter (Fig. 1, steps 3 and 4). Then the forgings are turned over 90 ° and run on its outer diameter using flat strikers. Next, the forging is turned over 90 °, installed on a backing plate with a hole 8 and the core is stitched with a conical piercing 6 from the side of its larger diameter. In this case, the extension 7 is used. With this firmware, part of the metal forming the otter 9 is removed from the workpiece (Fig. 1, steps 5 and 6). Subsequently, the forgings are calibrated by barrel-shaped or cylindrical piercing 10 (Fig. 1, step 7) and then it is rolled by free forging on the mandrel with flat dies or on a rolling machine and calibrated by height (Fig. 1, step 8).

The disadvantage of this method is that it cannot be used continuously cast billet of circular cross section with its inherent zone of axial porosity 3 (discontinuities). When using a continuously cast billet for this method, incomplete removal of low-quality (porous) metal from the middle of the forging (Fig. 1, step 6) occurs, as a result of which it rolls onto the inner contact surface of the treadmill of the outer bearing ring with its rolling body. To eliminate this drawback, it is necessary to increase the metal consumption for stock to remove the defective metal.

Figure 2 schematically shows the steps of the manufacturing process of annular forgings for bearings by free forging of the proposed method.

As the initial one, a continuously cast round billet 15 is used, which is divided into measured billets 2, and from the two ends of the measured billets 2 obtained as a result of cutting the continuously cast billet 15, a local marking of cavities in the axial zone with a conical piercing 6 is made up to 1 / 5-1 / 4 of the height of the workpiece 2 (figure 1, steps 1, 2 and 3). After that, the measured workpiece 2 is deposited as a whole until the end surfaces are aligned with the formation of an intermediate back barrel relative to the forging axis (Fig. 1, step 4). As a result, the zone of central porosity is localized near the axial zone of the forging, not propagating to peripheral regions relative to the axis of the forging (Fig. 1, step 4). Then the workpiece is forged to the required dimensions in height and diameter according to standard technology (Fig. 1, step 5), followed by cutting out the central part (Fig. 1, steps 6 to 8), piercing the hole with a hole (Fig. 1, step 9) and obtained annular forging roll forging on the mandrel with a flat top striker or on a rolling machine (figure 1, step 10).

In addition, in order to expand the standard sizes of bearing rings obtained by free forging from a continuously cast billet 15, and to reduce the dimensions of the axial discontinuity zone 3 of a continuously cast billet 15 for its subsequent removal when flashing before cutting a continuously cast billet 15 into dimensional billets 2, forging is carried out continuously cast billet 15 with a feed to the length of the striker, using the underrun acceleration 14 of a semicircular section mounted on the workpiece along its longitudinal axis under the upper striker 1. Broaching wire Yat under the scheme:

- pushing the acceleration 14 into the body of the continuously cast billet 15 (Fig. 3, stage 1 and 2);

- tilting continuously cast billet 15 along the longitudinal axis of 180 ° (figure 3, step 3);

- pushing the acceleration 14 into the body of the continuously cast billet 15 (Fig. 3, step 3);

- canting of continuously cast billet 15 by 90 ° (Fig. 3, step 4);

- pushing the acceleration 14 into the body of the continuously cast billet 15 (Fig. 3, step 5);

- canting of continuously cast billet 15 by 180 ° (Fig. 3, step 6);

- pushing the acceleration 14 into the body of the continuously cast billet 15 (Fig. 3, step 6);

- forging a broach on a flat strikers 1 and 4 on a given diameter (figure 3, steps 7 to 10).

Sources of information

1. Okhrimenko Y.M. Forging technology. M.: Engineering, 1966, 599 p. (p. 199-211).

2. Stamping of ring blanks / Lviv D.S., Rozhdestvensky Yu.L., Abramov A.V., Litvak L.K. // M .: GNTI Mashlit, 1958, 182 p. (p. 60-61).

Claims (2)

1. A method of manufacturing an annular forgings for bearings by free forging, including cutting the total workpiece into dimensional, heating of the measured blanks for forging, followed by incomplete flashing and running in the outer diameter using flat strikers, installing on a backing plate with a hole and flashing the core with tapered piercing sides of its larger diameter, calibration of the forging hole with barrel-shaped piercing, rolling the workpiece on the mandrel, calibrating it in height, characterized in that the initial discontinuous cast billet of circular cross section, and from two ends of measured billets obtained as a result of cutting continuous cast billet, localization of cavities in the axial zone is carried out with tapered piercing by the amount of 1 / 5-1 / 4 of the height of the billet, after which the measured billet is upset completely until the end surfaces are aligned with the formation of an intermediate reverse barrel relative to the axis of the forging. 2. The method according to claim 1, characterized in that before cutting the continuously cast billet into measured billets, forging is carried out by pulling a continuously cast billet with a feed to the length of the striker, using the undermining of a semicircular section mounted on the workpiece along its longitudinal axis, under the upper striker, moreover, the broaching is carried out according to the scheme: pushing the acceleration into the body of the workpiece; 180 ° continuous casting of the blank along the longitudinal axis; indentation of distillation into the body of the workpiece; tilting of the continuously cast billet along the longitudinal axis by 90 °; indentation of distillation into the body of the workpiece; 180 ° continuous casting of the blank along the longitudinal axis; indentation of distillation into the body of the workpiece; forging by broaching on flat strikers for a given diameter.

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