SU1245383A1 - Method of drawing hollow articles from a sheet blank - Google Patents

Abstract

The method of stretching hollow articles from the sheet blank by forming a force of deformation on the central part of the blank to form on its peripheral part of conical corrugations with a height increasing to the periphery and subsequent straightening them, in order to improve quality. products, increasing productivity by straightening the corrugations continuously throughout the entire stretching process, limit the height of the corrugations during stretching, and straighten them out consistently, starting from the central part, when it flutes taper angle is determined from the expression rf ij, 7552. Where and is the exponent of the equation for the power approximation of the material hardening curve; t is the thickness of the workpiece; G is the radius of the product being pulled out; (о- radius of the workpiece. d Ф (Л

Description

The invention relates to the processing of metals by pressure and relates to the extraction of hollow articles from a billet.

The purpose of the invention is to increase productivity by straightening corrugations continuously throughout the entire stretching process, in order to improve product quality.

FIG. 1 shows a device for carrying out the proposed method, a longitudinal section; Fig. 2 shows the device at the initial moment of drawing; in fig. 3 - the same, in the intermediate stretch point; in fig. 4 - the same at the final moment of stretching.

The device contains a punch 1, the matrix 2, the clamp 3 and the workpiece 4.

The method is as follows.

in a way.

Flat sheet blank 4 is placed between the matrix 2. and the clamp 3 (figure 1). The clamp 3 draws the punch 1 until it is supported in the matrix 2 and pressed against the latter. The blank 4 in the initial position is in a narrowing cavity and not pressed against the matrix 2.

The central part of the preform is affected by the deformation force from the side of the punch 1 to the formation on its peripheral part of conical radial corrugations with increasing height to the periphery, while the height of the corrugations is limited, and the angle of the corrugations of the corrugations is determined from the expression

  l 7552-n-t

(I - | -). about

where and is the exponent of the equation for the power approximation of the material hardening curve;

 t is the zagot thickness, is the radius of the product being stretched;

RQ is the work radius. The radial profile of the self-formed corrugations corresponds to the angle cL between the mirror of the matrix 2 and the clamp 3. After the formation of stable corrugations during the further course of the punch 1, the flange of the blank 4 is pulled out by discharging

2453831

The formation of these corrugations in the narrowing cavity (Fig. 3) is consistent, starting from the central part. At the end of the stretching process, the corrugations located at the outer edge of the flange are straightened in the narrowest part of the tapering cavity (Fig. 4). Then punch 1, clamp 3 is retracted and the product is removed (not shown).

ten

The formation of corrugations at the beginning of the stretching process occurs by bending in the absence of tangential plastic deformation of compression and

) 5 is accompanied by a decrease in the diameter of the blank 4. Therefore, the thinning of the dangerous section of the blank 4 on the punch 1 at the beginning of the drawing process is absent. Profile of corrugations in axial

20 is formed by a fixed clamp pressed to the matrix 2 and corresponds to the angle oL between the mirror of the matrix 2 and the clamp 3. The angle is found from the condition providing

25 formation of stable corrugations without the possibility of converting corrugations into folds. The angle d depends on the thickness of the material of the workpiece 4, the radius R ,, the workpiece 4, the radius g,

30 of the finished product and the index and strengthening. The corrugated flange is pressed all over its surface against the mirror of matrix 2 and pressing 3 "This ensures an even distribution of friction forces along the flange during the entire stretching process, which contributes to the reduction of tensile stresses and thinning in hazardous section of the workpiece 4 on the punch 1. The flange of the workpiece 4 is stretched by pressing the clamp 3 fixed to the matrix 2, therefore the flange of the blank 4 is pressed against the mirror, the matrix 2 and the clamp 3 during the stretching process due to the deformation of the flange. When straightening corrugations are straightened out during the stretching process, their height continuously changes. This provides the condition for self-regulation of the force of pressing the flange.

 Everything described above leads to a decrease in the tensile stresses in the dangerous section of the workpiece 4 on the punch 1 during stretching and, accordingly, to a decrease in thinning.

55 in this section, and also excludes folding on the flange. Therefore, the proposed method allows to demonstrate the degree of deformation in 35

40

45

3

cooking, and hence the height of the finished products.

The straightening of the corrugations according to the proposed method occurs from the beginning of the end of the draw, i.e. during the whole process of plastic deformation, as a result of which productivity is increased.

The drawing method was tested by drawing cylindrical glasses with a diameter of 54 mm with a trot of 20 mm from a billet with a diameter of 90 mm and a thickness of 0.3 mm, AMts material with a reinforcement index and 0.255; with a diameter of 7 m with a height of 8 mm from the workpiece, a diameter of 18 mm and a thickness of 0.25 mm, material Х18Н10Т with a reinforcement ratio and 0.239.

For comparison with the base object, four batches of parts of 100 pieces each are made. In the first batch of 100 pieces, parts are made of AMts material with the indicated dimensions by the extrusion method according to the base object for two drawing operations. The number of defective parts due to ruptures and folds in the first batch of 24 pieces, and the thinning of finished parts 12% In the second batch of 100 pieces. parts made of AMC material with the same dimensions of the proposed method with the angle of the radial profile of the corrugations with. 033 in one pull operation. Number of defective parts5

45383.-4

due to breaks in the second batch, 3 lei, and thinning of finished parts 3%. In the third installment 100 pcs. parts are made of material X18H10T with the indicated dimensions by the method of stretching according to the basic object for three drawing operations. The number of defective parts due to ruptures and folds in the third batch is 35 pcs., And the thinning of finished parts is 15%. In the fourth installment 100 pcs. The parts are made of material Х18Н10Т with the same dimensions as proposed by the method with the angle of the radial profile of the corrugations. “4 l 43 for one exhaust operation. The number of defective parts breaks in the fourth batch of 4 pcs., And the thinning of finished parts 7% „

ten.

t5

Compared with the known methods, the use of the proposed stretching method provides an increase in the degree of deformation and, accordingly, a decrease in the number of exhaust operations by a factor of 2 to 3, as well as a reduction in rejects by 85-95% due to the absence of breaks and folding. In addition, the range is extended. use of the proposed method. extraction due to the insignificant loss of the dangerous section of the workpiece on the punch for the manufacture of high quality parts from foil,. billet thickness up to 0.1 mm.

FIG.

FIG. 2

FIG.

Editor L.Gratillo

Compiled by B. Muslimov Tehred G. Gerber

Order 3942/6 Circulation 783 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Ra usushka nab. 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Fig.Ch

Proofreader Oh, Lugov

Claims (1)

A method of extracting hollow articles from a sheet stock by acting on the central part of the blank with a deformation force to form conical corrugations on its peripheral part with increasing height to the periphery and subsequently straightening them, which means that in order to improve product quality and increase productivity by straightening corrugations continuously throughout the entire drawing process, the height of the corrugations during drawing is limited, and their straightening is carried out sequentially, starting from the central part, including the angle ōnusa corrugations determine the expression c. b'552 _L n-t ___ (. where and is the exponent of the equation of power-law approximation of the hardening curve of the material; t is the thickness of the workpiece; g is the radius of the product being drawn; J _about - the radius of the workpiece.