SU1428513A1 - Method of producing hollow articles from sheet blank with a hole - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in the manufacture of hollow articles with a hole such as rings, clutch discs, flanges, etc. The goal is to prevent the loss of stability of the workpiece during its processing by reducing the amount of tensile stresses in the areas of the rounding of holes. The essence of the method is that the billet 7 of elongated shape with a hole before applying tensile and compressive forces is subjected to preliminary inversion in two stages. At the first stage, the sections of the wall of the workpiece 7 in the zone of curves to the vertical position are subjected to eversion using the punch 1 and the matrix 3. To determine the length of the sections subjected to the eversion, the calculated dependence is presented. In the second stage, the remaining parts of the workpiece are subjected to the shortening. 7 il. (L

Description

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The invention provides for the pressure treatment of sheet metal blanks and can be used for

production of hollow products with a hole like rings, clutch discs, flanges, etc.

The purpose of the invention is to prevent the loss of stability of the workpiece by reducing the magnitude of the tensile stresses in the rounding zones.

holes.

Figure 1 shows the initial preparation; Fig. 2 shows the workpiece after local inversion of the rounding zones of the hole (in three projections); in Fig. 3, the workpiece after the final inversion of the walls to their vertical position (in two projects)}

Fig. 4-1 is an example for local inversion of the rounding zones of the workpiece; FIG. 3 shows a stamp for inversion and the remaining straight horizontal sections; in fig. 6 - finished product of the type of ring with vertical walls, after distribution; figure 7 is a product of the type of ring with horizontal walls, obtained after the operation of crimping the ring, presented in Fig.6.

 Example. The manufacture of a hollow ring-type product with horizontal wall w, having the following dimensions: h 3.5 mm, outer diameter of the ring is D 146.5 mm, wall width is 15 mm, the inner diameter of the ring is d 113.5 mm. The dimensions of the workpiece are determined from the condition of constancy of the volume: length of the workpiece, mm, width of the workpiece, 50 mm, outer radius of rounding of the workpiece, mm, radius of rounding of the hole Rj, 10 mm, hole length is 170 mm, distance between centers A 150 mm. Material - steel 30 HGSA.

With the help of a stamp (Fig. 4) consisting of the punch 1, the matrix protrusions 2 and the matrix 3, a reversal of the rounding zones of the bore hole in the length of 38 mm is made. The initial preform is mounted on the matrix protrusions 2 and during the downward movement of the punch 1, the rounding zones are locally inverted to their vertical position. The preform obtained in the first inversion stage is shortened to L 177 mm. Inversion of the remaining straight parts of the workpiece can

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carried out using a punch (Fig. 5) consisting of a punch 4, a die 5 and a stand 6. The workpiece 7 is pushed down the punch 1 into the gap between the punch 4 and the die 5 to position 8 due to the application of axial forces P and moment M according to the scheme (figure 2).

As a result of the inversion operation, the original elongated workpiece with a hole takes the form shown in FIG. 3, with the radius of curvature of the outer surface of the workpiece varying from Cc 25 mm to Rc 13.5 mm. The decrease in the Cc value causes a significant decrease in the level of tensile stresses upon receipt of an item such as a ring with vertical walls (Fig. 6) from the intermediate-shape preform shown in Fig. 3. To obtain a ring with horizontal walls (Fig. 7) from a ring with vertical walls, a well-known stamp is used to burn round cylindrical billets with vertical walls. I

The local inversion of the horizontal walls in the zones of the hole rounding up to their vertical position is realized on the length

L (2 ... 2.3) Kc-1,6Rj,

where L is the length of the inverted section of the wall of the workpiece;

Cc is the radius of curvature of the outer surface of the workpiece;

Rg is the radius of curvature of the inner surface of the workpiece hole.

The introduction of an additional step of inversion of the original billet of an elongated shape with a hole at the bottom to produce round hollow products allows to deform all structural steels,. including malooplastic, without the appearance of friction on the surface of the oblong hole. Obtaining products from an oblong blank with a hole significantly increases the utilization of the metal to a value of K. 0.85 compared to cutting the outer contour and punching holes used by them. for low-plastic steels, when the coefficient of use is K 0.45.

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Claims (1)

Claim A method of manufacturing hollow products from a sheet stock with an opening, namely, that the shape and dimensions of the sheet stock, an elongated shape with an opening having a size larger in the direction of one axis and smaller than the hole size of the finished product in the other direction, are changed by applying tensile and compressive forces to the surface of the workpiece, characterized in that, in order to prevent loss of stability by reducing the magnitude of tensile stresses in the curvature zones of the hole, the workpiece before deformation with the application of tensile and compressive forces subjected to a local eversion of its horizontal walls in the curvature of the hole to their vertical position along the length L = (2 ... 2,3) R _H - 1,6 Rj, where L is the length of the turned part of the wall of the workpiece; R „is the radius of curvature of the outer surface of the workpiece; R _e is the radius of curvature in. the surface of the hole ed of the workpiece, with the subsequent eversion of the remaining rectilinear sections of the workpiece with the application of axial forces on the previously turned walls of the workpiece in the curvature zones of the hole. FIG. 2 142851 3