RU2447966C2 - Die for closed die forging - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in dies for making complex-shape forgings. Die includes top and bottom parts provided with top and bottom die bed contours and limiting ledges made on edges of said contours. Ledge inner surface are provided with bed contours producing, together with said top and bottom contours, an integrated closed surface along forging edges. Die top and bottom parts may joint together along ledge side surfaces. Note here that forging lateral projection contour does not cross lateral projection of die opening plane in the same direction. Surfaces of top and bottom die bed contours may be arranged at angle to horizontal plane.

EFFECT: higher precision of forgings, simplified withdrawal of forgings.

2 cl, 2 dwg

Description

The invention relates to the processing of metals by pressure, namely to die forging, and can be used as a stamp for the production of complex contour stamped forgings without stamping slopes on the outer side surface of the forgings, in particular for the manufacture of products from expensive metals and alloys.

Stamping in closed dies is characterized in that the die cavity remains closed during deformation. The gap between the movable and stationary parts of the stamp is constant and small, so that the formation of a burr is not provided in it. Closed stamps are characterized in that the engraving is done in one of the halves of the stamp, and the other half enters the first, locking it. The coupling of the half of the dies is made on cylindrical surfaces: on the punch on the outside, and on the matrix on the inside (Yu.V. Shevakin et al., Metal forming. - M.: Internet Engineering, 2005, p. 452). On presses, as a rule, the lower half of the die is stationary and forms a cavity (matrix) and movable and forms a protrusion (nucleon).

The main disadvantage of this stamp is the need to assign stamping slopes to the side surfaces of the part parallel to the direction of movement of the stamp parts. This leads to a decrease in the material utilization factor (CMM) during the machining of a stamped forgings part and to an increase in the complexity of machining the part. In addition, the forging is extracted from a deep cavity, which requires a forging system for the forging machine with a relatively large (in comparison with an open punch stamp) ejector stroke. In the case of stamps with small stamping slopes or without them, jamming of the forging in the deep cavity of the stamp is possible.

Known stamp for closed die forging, containing a matrix and a punch with protrusions offset from the engraving of the stamp and going when lowering the punch into the grooves made in the matrix and punch, while the plane of the engraving is located at an angle to the protrusions of the matrix and punch (A.S. No. 657901, IPC B2IJ 13/02, publ. 01/06/1978).

Since the projection value of the base of the engraving is greater than the projection of the height of the engraving, then the pressing forces of the matrix to the punch are greater than the forces repelling them in the horizontal direction, which completely eliminates the formation of a gap between them, and hence the burr.

The disadvantage of the stamp is the impossibility of pressing products with a significant height and complex surface configuration.

A stamp is known for closed volumetric stamping, containing upper and lower parts, on each of which along the edges of the engraving, opposite directional protrusions are made in pairs on mutually opposite sides, the inner surfaces of the protrusions are the walls of the engraving, which, when closed, form a quadrangular working cavity with stamping slopes ( AS No. 1050800, B21j 13/02, publ. 02/11/1982) - prototype.

The design of the stamp is technological in design and allows you to do without the use of ejection mechanisms, however, it does not allow to manufacture products without stamping biases.

The objective of the invention is the manufacture of forgings by the method of closed stamping without stamping slopes but the outer side surface of the forgings, the exclusion of jamming of the forgings with closed stamping, the ability to perform closed stamping on forging machines without an ejection system or with a small ejector stroke.

The technical result achieved by the implementation of the invention is as follows:

- saving stamped metal by improving the accuracy of forming the side surfaces of the stampings: the exclusion of stamping slopes;

- increasing the productivity of the stamping process by eliminating the time to extract stuck forgings, as well as the ease of removing the forgings from the stamp;

- improving the maintainability of the tool due to the quick and cheap replacement of the failed stamp element.

The specified technical result is achieved in that the stamp for closed volumetric stamping of complex contour forgings, containing the upper and lower parts with restrictive protrusions along the edges of the engravings, is characterized in that the upper and lower engravings of the stamp parts, as well as the engravings made on the inner surfaces of the restrictive protrusions, form a single closed surface according to the configuration of the stamped forgings, while the upper and lower parts can mate on the side surfaces of the protrusions in such a way that the contour of the side projection and stamping, located in the engraving of the stamp after the stamping process does not cross the contour of the side projection of the plane of the connector of the stamp in the same direction.

To prevent the formation of a gap between the upper and lower parts of the stamp, the planes of the upper and lower engravings are located at an angle to the horizontal plane.

The invention is illustrated by drawings, which show: in figure 1 - the upper and lower parts of the stamp and one of the possible stamped products, in figure 2 - section of the stamp.

The stamp contains (Fig. 1) the lower half of stamp 1 (hereinafter the lower stamp) with a restrictive protrusion 2, which is attached to the lower die holder (not shown), and the upper half 3 of the stamp (hereinafter the upper stamp) with the restrictive protrusion 4 - to the upper die holder ( not shown).

The stamp works as follows.

The upper die holder together with the upper die 3 is retracted to its highest position to provide access to the engraving 10 of the lower die (figure 2), on which the workpiece 6 is installed. Next, a working stroke is made, during which the lower and upper dies are first touched along the connector plane 7 and 8, and then the workpiece touches and horizontal engraving 9 of the upper stamp. Under the action of the forging machine, the workpiece is deformed. The lateral surfaces of the workpiece are formed by engravings 11, which are located on the surface of the limiting protrusions 2 and 4. Normal stresses distributed across the horizontal engraving 9 (Fig. 2) of the upper and horizontal engravings 10 of the lower stamp, due to the inclination of the engraving from the very beginning of the workpiece deformation, cause the horizontal pressing force proportional to the developed press force, which prevents the formation of a gap between the upper and lower stamp on the surface of the connector and extrusion of a burr into it. The inclination of the engravings, made to create a clamping force, also prevents the workpiece from falling out of the lower stamp and ensures stable styling.

The plane of the connector dies 7 and 8 serve simultaneously and the guides of the stamp. After the end of the working stroke, the upper die 3 is pulled to its highest position, giving access to the stamped forgings 12 located in the engraving of the lower stamp 1. If there is a pushing system, the pressed forgings 12 are pushed upwards, after which they can be easily pulled up or sideways (towards themselves) . When stamping on a forging machine without an ejection system, the forging is also removed up and to the side, holding the forging by the stamping elements protruding from above (ribs, bosses, etc.).

The proposed design of the closed stamp eliminates most of the disadvantages inherent in closed stamping, and therefore can be used instead of open breakdown stamps in cases where the use of closed stamps of known designs is impossible.

The proposed stamp was tested in the manufacture of stampings from titanium alloys of complex geometric shapes. For example, for a landing gear part of a passenger aircraft, such as a 74 kg fork made of Ti-10V-2Fe-3Al alloy, when replacing open breaker dies with a closed stamp of this design, an increase in the utilization rate of the forging blank material (CMM) by 20% was achieved due to the exclusion of metal loss in a flake. In addition, the number of die transitions was reduced from 3 to 2, and due to the exclusion of stamping slopes on the outer side surfaces, the mass of the stamped forging itself was reduced by 2%.

Claims (2)

1. A stamp for closed volumetric stamping of complex-contour forgings, containing the upper and lower parts made with engravings and restrictive protrusions at the edges of the engravings, characterized in that the upper and lower parts are respectively made with upper and lower engravings, and the restrictive protrusions are with engravings on the inside surfaces forming with these upper and lower engravings a single closed surface according to the configuration of the stamped forgings, while the upper and lower parts are able to mate on the side surfaces to the protrusions in such a way that the side projection contour of the stamped forgings does not intersect the side projection contour of the stamp connector plane in the same direction. 2. The stamp according to claim 1, characterized in that the planes of the upper and lower engravings are located at an angle to the horizontal plane.

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