RU2082523C1 - Method for shaping hollow axially symmetrical parts - Google Patents

Abstract

FIELD: plastic metal working, namely, production of thin-wall members of pipeline systems by cold forming of tubular blanks with use of elastic medium pressure. SUBSTANCE: tubular blank with flexible filler in the form of cylinder is arranged in split die. By means of punches acting in axial direction onto ends of blank and filler, they are upset with different speed. Relation between speed of filler unsetting and speed of blank upsetting is selected according to expression given in description of the invention. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to the processing of metals by pressure, in particular to cold stamping using the pressure of an elastic medium, and can be used to obtain thin-walled elements of pipeline systems.

A known method of manufacturing hollow products with bends such as tees and crosses from a pipe billet, comprising molding with internal pressure and an end draft of the billet, in which the bend is first formed on the billet with increased internal pressure, which is then reduced by 1.5 to 2 times, and the final molding the products are carried out mainly by the end draft of the workpiece [1]
The decrease in internal pressure during the final molding of the outlet allows you to reduce the contact pressure between the workpiece and the die and prevent significant thinning of the wall of the outlet.

 However, since the magnitude of the internal pressure is a function of the precipitate size of the elastic filler, in the case of molding products, for example axisymmetric, in which the preform is formed by increasing the volume of its internal cavity, a decrease in internal pressure will be accompanied by a decrease in the amount of displaced filler volume. This leads to under-shaping and folding during the final molding of the product.

A known method of forming axisymmetric parts, including the distribution and simultaneous axial compression of the tubular workpiece with an elastic filler, in which the missing volume of elastic filler formed by increasing the volume of the workpiece is replenished by upsetting additional elastic material [2]
In the known method, the simultaneous application of radial distributing and axial compressive forces prevents the formation of folds (loss of stability of the workpiece material).

 However, in the known method, the missing elastic filler is supplied at the end of the axial upsetting of the preform, and therefore, shaping during axial upsetting is accompanied by a lack of volume of the elastic filler. As a result, it is possible to obtain high-quality parts with a small coefficient of distribution.

 The proposed method allows to expand the range of manufactured parts, preventing the loss of stability of the workpiece material due to lack of filler, in the formation of parts with a high coefficient of distribution.

относительное изменение объема наполнителя на участке раздачи детали;
V_п.д. объем полости детали на участке раздачи;
V_п.т. объем полости заготовки длиной, равной высоте участка раздачи;

относительное изменение объема материала заготовки на участке раздачи;
V_д объем материала детали на участке раздачи;
V_т объем заготовки длиной, равной высоте участка раздачи.The technical result of the invention is achieved by the fact that in the known method of forming hollow axisymmetric parts by distribution, including axial draft of the tubular billet with elastic filler in the stamp, the billet and filler are deposited at different speeds, determining the ratio between them from the condition
v _n / v _z = Δv _n / Δv _z (1),
where V _{n the} speed of the axial upsetting of the filler;
N _s the axial draft rate of the workpiece;

the relative change in the volume of the filler in the distribution area of the part;
V _p.p. the volume of the cavity of the part in the distribution area;
V _p.t. the volume of the cavity of the workpiece with a length equal to the height of the distribution area;

relative change in the volume of the workpiece material at the distribution site;
V _{d the} volume of the material of the part in the distribution area;
V _{t the} volume of the workpiece with a length equal to the height of the distribution area.

 The axial sediment of the tubular billet and elastic filler with different speeds, with the ratio between them (1), allows you to replenish the volume of the filler in accordance with the change in the volume of the cavity of the workpiece as it is forming.

 The drawing shows a diagram of the formation of an axisymmetric part: on the left is a tubular billet with an elastic filler before axial upset; molded part to the right.

 The method is as follows.

The tubular billet 1 with an elastic filler 2 in the form of a cylinder is placed in a detachable matrix 3, while the geometric parameters of the billet and filler are selected from the condition of equal volume, respectively, of the part and its internal cavity. Then, the corresponding axial compression punches 4.5 are brought to the ends of the workpiece 1 and filler 2 and they begin to be deposited at different speeds under the action of axial forces, while the ratio between the sedimentation rate of the filler U _n and the settling rate of the workpiece U _{s is} selected from relation (1).

For example, when forming from a tubular billet of ⌀ 80 mm with a wall thickness of 1 mm, the adapter parts are 100 x 80 with a distribution section length of 82 mm, axial settlement of the filler and the billet is carried out at a ratio of speeds of U _n / U _s 2.3.

Claims (1)

The method of forming hollow axisymmetric parts by distribution, including axial upsetting of a tubular billet with an elastic filler in a stamp, characterized in that the billet and filler are deposited at different speeds, determining the ratio between them from the condition
V _n / V _s = ΔV _n / ΔV _s ,
where V _{n the} speed of the axial upsetting of the filler;
V _{3 the} speed of the axial draft of the workpiece;
ΔV _n is the relative change in the volume of the filler in the distribution area;

V _{p . d the} volume of the cavity of the part in the distribution area;
V _{p . t is the} volume of the cavity of the workpiece with a length equal to the height of the distribution section;
ΔV _{s the} relative change in the volume of the workpiece material in the distribution area;

V _{d the} volume of the material of the part in the distribution area;
V _{t the} volume of the workpiece with a length equal to the height of the distribution area.