RU2299110C2 - Hollow part forming method - Google Patents

Abstract

FIELD: plastic working of metals, possibly manufacture of hollow parts such as sleeve type parts with central protrusion on inner surface of bottom, namely artillery shell cases.

SUBSTANCE: method comprises steps of backward pressing out of initial blank and shaping bottom portion having protrusion on inner surface during several transitions. After backward pressing out transition, blank is drawn at several transitions. Bottom portion with central protrusion is formed during two transitions, namely: at transition for preliminarily shaping central protrusion and at transition for finally forming bottom portion. Preliminary forming is realized during transition of backward pressing out of initial blank by means of inner punch with recess. Final forming is realized by means of inner punch with recess and outer punch with protrusion.

EFFECT: improved quality of articles.

5 dwg

Description

The invention relates to the processing of metals by pressure, in particular to the technology of cold forming, and can be used for the manufacture of hollow parts of the type "glass" having a central protrusion on the inner surface of the bottom, for example, artillery shells.

A known method of manufacturing hollow parts with a central protrusion on the inner surface of the bottom part by stamping with a punch in a matrix, including backward extrusion of the original workpiece and the formation of the bottom part with a central protrusion on the inner surface (see SU A.S. 1792788 A1, 02/07/1993, , B21K 21/06).

The disadvantage of this method is the failure to obtain the exact geometry of the central protrusion on the inner surface of the bottom part in accordance with the design documentation when stamping the bottom part due to insufficient set of metal to completely fill the inner cavity of the inner punch when the bottom is formed by the outer punch.

Due to the insufficient metal volume during the formation of the bottom protrusion, incomplete pressing of the protrusion occurs, which does not exclude (does not eliminate) the central porosity that takes place in the initial billet (in the center of the bar) (see Fig. 5).

This reduces the workmanship of the part.

The objective of the invention is to improve the quality of the obtained parts by ensuring the implementation of the Central protrusion on the inner surface of the bottom part in accordance with the design documentation and the exclusion of porosity on the protrusion due to the complete pressing of the bottom.

The required technical result is achieved by the fact that in the method of manufacturing hollow parts with a central protrusion on the inner surface of the bottom part by stamping with a punch in a matrix, including back extrusion of the initial workpiece and the formation of the bottom part with a central protrusion on the inner surface, reverse extrusion of the initial workpiece and the formation of the bottom part with a central protrusion on the inner surface is carried out by transitions, after the reverse extrusion transition, the workpiece is drawn out along transitions, and the formation of the bottom part with a central protrusion on the inner surface is carried out in two transitions: preliminary formation of the central protrusion and the final formation of the bottom part, while the preliminary formation of the central protrusion is carried out at the transition of reverse extrusion of the original workpiece using an internal punch with a hollow, and the final formation the bottom part is produced by an inner punch with a hollow and an outer punch with a protrusion.

The combination of distinctive features made it possible to obtain high-quality performance of the bottom due to preliminary metal recruitment at the backward extrusion transition, in terms of ensuring compliance with the design documentation requirements, and also eliminates bottom porosity that affects the functioning of the cartridge during use, eliminates the possible breakthrough of gases through the igniter capsule the internal cavity of the assembled cartridge and its operation.

Therefore, each distinguishing feature is “essential” and necessary, and their combination in a stable relationship is sufficient to achieve a “novelty” of quality, that is, a new effect of the sum that is not inherent in the characteristics of disunity.

Figure 1 shows a diagram of the manufacture of parts for transitions (I - the workpiece, II - reverse extrusion, III-V - exhaust transitions, VI - stamping the bottom);

Figure 2 - arrangement of the tool during reverse extrusion;

Figure 3 - arrangement of the tool at the exhaust transitions;

Figure 4 - arrangement of the tool when stamping the bottom;

Figure 5 is a diagram of the shape of the protrusion of the bottom in a known method.

The method is as follows. From the rod by the method of hot screw rolling, a workpiece (I transition) is obtained having the correct (ball shape in the form of lentils) shape (Fig. 1), so there is no need to calibrate it.

At the second transition, reverse extrusion of the workpiece 1 by the punch 2 into the matrix 3 is carried out.

At this transition, the preliminary formation of the central protrusion 4 is performed on the inner surface of the bottom part on the workpiece 1 by the cavity 5 of the inner punch 2.

The ejector 6 blank is removed from the cavity of the matrix 3 (figure 2). Then produce exhaust transitions III-V, while the punch 7 also has a depression 8 (figure 3).

Stamping of the bottom part (VI transition) (figure 4) - the final formation of the bottom part and the protrusion 9 - produce a force of inner 10 and outer 11 punches.

The punch 10 has a cavity 12 equal to the protrusion of the finished part 13 in accordance with the requirements of the design documentation, and the punch 11 has a protrusion 14 with the shape and dimensions corresponding to the cavity 15 of the finished part 13.

Compared with the prototype, the invention improves the quality of the part obtained not only by ensuring the implementation of the central inner protrusion (exclusion of underpressure) in accordance with the design documentation, but also by eliminating porosity on the protrusion due to the complete pressing of the bottom (figure 5).

The invention is industrially applicable.

Confirmation is the fact that positive work has been done to eliminate the shortcomings in ensuring the implementation of the central protrusion on the inner surface of the bottom in accordance with the design documentation and the exclusion of porosity on the protrusion at FSUE “PO Plant named after Sergo”.

Claims (1)

A method of manufacturing hollow parts with a central protrusion on the inner surface of the bottom by stamping with a punch in a matrix, including backward extrusion of the original workpiece and the formation of the bottom part with a central protrusion on the inner surface, characterized in that the extrusion of the original workpiece and the formation of the bottom part with the central protrusion on the inner surface is carried out in transitions, after the reverse extrusion transition, the workpiece is drawn out in transitions, and the formation of the bottom h Stitches with a central protrusion on the inner surface are carried out in two transitions: preliminary formation of the central protrusion and final formation of the bottom part, while the preliminary formation of the central protrusion is carried out at the reverse extrusion of the initial workpiece using an internal punch with a hollow, and the final formation of the bottom part is performed with an internal punch with a hollow and an external punch with a ledge.

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