SU1465152A1 - Method of producing thin-walled shells - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular, to methods for producing thin-walled shells by means of rotary stretching. The goal is to improve the quality of the parts produced and the utilization rate of the material, as well as expanding the range of the parts obtained. - The profiled tubular billet is further strengthened by a cold rotary drawing with thinning on the mandrel. This results in an increase in the yield strength of the material in the direction of deformation. Additional hardening of the workpiece is combined with the profiling of its wall. This allows you to eliminate the loss of stability of the molded workpiece when it is distributed with heating and to expand the range of the parts produced. 1 hp f-ly, 3 ill. (ABOUT

Description

one

The invention relates to the processing of metals by pressure, namely to sheet metal forming, and can be used in mechanical engineering for the production of equal thickness axisymmetric shells from tubular blanks.

The aim of the invention is to improve the quality of the parts produced and the utilization rate of the metal, as well as expanding the range of the parts obtained.

Fig. 1 is a diagram of the uneven hardening of the workpiece by cold rotary drawing; in fig. 2 shows a distribution scheme for a hardened and profiled workpiece (upper half, initial condition, and lower half — final position); Fig. 3 shows a nomogram for calculating the required distribution of the wall thickness of the workpiece S along the component of the workpiece for a given distribution of the extrapolated limit.

her material yield d

TO

The method is carried out as follows.

The initial tubular billet (cylindrical with constant wall thickness) is subjected to uneven hardening along its length by the method of cold plastic deformation, providing an increase in the yield strength of the material from the edge of the billet. Hardening can be carried out by various methods, for example, by successively crimping and dispensing a pipe, a detail of the initial geometry with variable mechanical characteristics of the material along the generator can be obtained. Then, the initial blank is profiled according to

ate

ate N)

the wall crest, providing the greatest thickness of the edge of the workpiece.

Profiling of the workpiece in thickness along the generatrix can be carried out in various ways: by machining the workpiece with chip removal, chemical etching, etc.

In the general case, the distribution of wall thickness over the length of the workpiece depends on the degree of shape change of the workpiece (on Kp), on the distribution of the mechanical properties of the material in the hardened workpiece, on the heating temperature of the material during distribution,

Where

. the contact of the received part.

Determine the required wall thickness by dubbing, if the material is hardened, can be solved by the equation of the shell element, the condition, the conditions of incompressible stress connection and the dependence of the material on the deformation and softening p 15 The final solution is dSs dSs SjxRa, dHl

dR S R

 (i + Z, v R Zj d & s Zv.

S tgo Zj Zi dlT Zl Ij, sin5

dRRZl

S3-z

contact friction and the geometry of the resulting part.

The required distribution of the wall thickness along the preform forming component, if the workpiece material is unevenly strengthened, can be determined by jointly solving the equilibrium equation of the shell element, the conditions of elasticity, the conditions of incompressibility, the equation for the connection of stresses and strains, and the dependence of the yield stress of the material on the strain strengthening and weakening when heated. The final solution is: dSs dSs SjxRa,. dHl - - “sinc,

Z

zl

dR S R

Zj d & s Zv.

Zi dlT Zl Ij, sin5

(one)

 S - R 3 S S S

D (And the current thickness value

billet walls;

the length of the workpiece;

current radius received

details;

radius of the original tubular

blanks;

const;

wall thickness obtained

details;

const;

angle between tangent to;

the shell and its axis of symmetry

rii;

coefficient of friction between

billet and punch;

 ft - 1 5V

Zo

the yield stress of the material;

meridional shell radius.

d6s value

is defined by the expression

(6, /

P-1P

Rn

R3

r-u-t.)

e. ,

(2)

where D is the extrapolated limit

turnover; P - hardening module;

T - temperature coefficient; t is the heating temperature of the material, trial, t f (R);

t is the temperature for determining the mechanical properties of a material: 6m „-P.

Solution (1) is carried out by numerical integration under boundary conditions (2): R, 83 S /.

Calculations show that .strengthening the zone of force transmission increases by 1.4–1.6 times the limiting possibilities.

35 form change from Kp 0.5, 3, ceteris paribus.

In order to increase the utilization of the material of the workpiece, the hardening of the tubular workpiece and its

40 profiling thickness combined) T in one operation. FIG. Figure 4 shows the hardening and profiling of the original billet using the rotary stretching method, with which a hardened and shaped billet 1 is obtained by thinning the billet wall on the rotating mandrel 2 using a squeezing roller 3. The required thinning of the wall from the edge of the billet is determined by the expression (1 ) by the method of successive approximation. First, the calculation is carried out (1) under the condition of a linear increase in the yield stress 6g

55 along the length of the workpiece: the distribution of the wall thickness of the workpiece (Sj) is determined, the distribution 6 is refined depending on the wall thinning, etc.

The process of distribution of the resulting workpiece 1 (Fig. 2) consists in the axial movement of the workpiece 1 relative to the punch 4, resulting in a finished part 5. The distribution process is carried out under those temperature-speed conditions that were included in the calculation of the wall thickness distribution blanks 1 (parameters 3-, t).

Example. The method was tested in the manufacture of thin-walled conichenes with equal thickness and conical details with a diameter difference of 76:28 (distribution coefficient of 0.37). The process was limited to the destruction of the workpiece on the edge. Material utilization factor is 0.95.

Claims (3)

1. A method of manufacturing thin-walled shells, comprising forming and strengthening a tubular billet along a thickness of 20 weighty details from material AMgZM. The angle of conicity of the parts was 304, providing a maximum thickness of 0.9 mm. The original blank billet on its edge and the blank billet was 0 284.5 mm-hardened and profiled using the rotary stretching method, while ensuring the distribution of the yield strength of the material and the wall thickness in accordance with the dependence shown in FIG. 3. Calculation (1) is carried out with the following parameters: 6 ° 200 MPa, n 340 MPa, | u 0.1, y -0.004, with a linear distribution of the heating temperature of the punch from t 320 C at the top of the punch to t 430 C on a large basis, at a deformation rate of 2 i10 - 8 10 s -CH As a result, obtaining the required reinforced and profiled workpiece and its distribution according to the indicated modes were semi-following distribution with heating of the workpiece on a rigid mandrel, characterized in that and metal utilization rate, as well as advanced rhenium nomenclature obtained parts are unevenly shaped blank further 25 are strengthened along the length by cold plastic deformation, increasing the yield strength of the material in the direction of deformation, and the wall thickness of the workpiece during profiling 30 are formed in the direction of profiling according to the dependency. §§1 S, S3j; R3 dH: dR S r sine /. dS3 dR (1. | L).,  tgo ( current thickness billet walls; the current length of the stock; current radius of the received part; the radius of the original tubular billet, const; wall thickness of the resulting metal, S const; the angle between the tangent to the shell and its axis of symmetry; coefficient of friction between the workpiece and the punch;  | - - In / -; Bz k. Z 2 2 xln - + K j In - i 03 Equal-thickness conical parts with a difference in diameter of 76:28 (distribution coefficient 0.37). The process was limited to the destruction of the workpiece on the edge. Material utilization factor is 0.95. Invention Formula 1. A method of manufacturing thin-walled shells, consisting in the profiling and strengthening of the tube billet along the thickness of the core, ensuring the maximum thickness of the billet at its edge and end 20 5, ensuring the maximum thickness of the workpiece on its edge and the following distribution with heating the workpiece on a rigid mandrel, characterized in that, in order to improve the quality of the parts produced and the utilization rate of the metal, as well as to expand the range of the parts obtained, the profiled workpiece is additionally uneven 25 are strengthened along the length by cold plastic deformation, increasing the yield strength of the material in the direction of deformation, and the wall thickness of the workpiece during profiling 30 are formed in the direction of profiling according to the dependency. e, ensuring maximum workpiece on its edge §§1 S, S3j; R3 dH: dR S r sine /. R bj .. - l S3 40 2j. , fj - 5i + X 2, zl dR- 2.g Z .-, Z |, 45 50 55 Z3 3xln -; 3 24 3xln. Bs s is the yield stress of the material; R is the meridional radius of the shell. 2. A method according to claim 1, characterized in that the additional reinforcement is combined with the profiling of the wall of the tube blank. 3. A method according to claim 2, characterized in that the additional strengthening and profiling of the tubular billet is performed by rotating it with thinning the wall on the mandrel. (par2 / 3. J 3 bs O.S 0 Editor H. Gorvat fig Compiled by Beschekov Tehred L.Olninzh (go.mpa 360 280 goo 80 20 2. Corrector l. Patay