SU984570A1 - Method of producing box-shaped hollow articles - Google Patents

Description

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The invention relates to the processing of metals by pressure.

A known method of manufacturing hollow box-shaped products with rounded sections is by attaching strips of their short sides to the facets of a multi-faceted sheet blank, stretching the obtained semi-finished product and connecting the strips along their long sides.

The disadvantage of this method is the duration of the manufacture of products, due to the fact that after inserting a hollow product, the joints formed in it require their connection by an additional operation, electric welding. In addition, the carrying capacity of the products is reduced by 20-30 / o due to the presence of longitudinal welds on their side surface.

The purpose of the invention is to increase productivity and improve the quality of the finished product.

This goal is achieved by the fact that according to the method of manufacturing hollow box-shaped products with rounded sections and by attaching strips of

short side, stretching the obtained semi-finished product and joining strips along their long sides to the edges of the sheet blank, forming rounded side areas of the product during stretching, attach stripes of lower strength than the strength of the strips attached to the edges forming flat sections the product, and the connection of the bands on the long sides is carried out by shearing in the process of stretching.

The drawing shows a sheet polyhedron on a workpiece with strips of different strength attached to it, subjected to stretching and shearing.

The method is carried out as follows.

Sheet bands 2 and 3 are attached to the sheet blank 1 in the form of a polyhedron, for example by welding, with a thickness equal to the thickness of the blank 1 and a length corresponding to the stretch ratio.

It is known that when a multi-faceted product is stretched, the deformation along its perimeter is variable: the side walls are subjected to bending deformations. Tie, simply bend back, while in the corners (on rounded sections) stretching occurs. Therefore, to form rounded sections, a material with lower strength should be taken than for flat sections of the side surface of the product. To do this, use two groups of bands of different strength, and the strength of the bands can be achieved by hardening or heat treatment (quenching), or thermomechanical treatment. Different materials can be taken for this purpose, i.e. material of different strengths, for each group, while observing the required condition for the weldability of this pair of materials by shear. Less durable strips 2 are attached, for example by welding, to the zones of the workpiece 1 forming the rounded areas of the side surface of the product being forged (not shown), and the more durable stripes 3 to the zones of the workpiece 1 forming their flat parts.

After that, using a punch and die (not shown). carry out stretching. Only the flange part of the workpiece 1 will be subjected to the process of plastic deformation; the welded sheets will not initially be deformed. As the walls of the finished product form from the flange part of the preform 1 (the inner walls of which are shown by dotted lines), the strips 2 and 3 will be involved in the deformation zone. Due to the fact that strips 2 are subjected to stretching, and strips 3 are only flexible, and also because strips 2 have less strength than strips 3, their speed from the periphery to the center will be different: strips 2 will move with greater speed than stripes 3.

It is known that drawing occurs under the combined effect of radial and tangential stresses on the material being forged. For each pair of strips 2 and 3, which are in contact with each other along lines 4, tangential for stretching the voltage will be caused by normal forces, i.e. by forces perpendicular to the plane of the long sides of the bands, the radial for drawing tension will cause tangential for a pair of bands 2 and 3, the forces T acting in the plane of the long sides of the bands. Consequently, adjacent strips are compressed by force N and shifted in the plane of separation by force T. The simultaneous simultaneous action of forces N and T at their optimum values and optimal ratios between them provides the connection (cold welding by shear) of strips 2 and 3 through the lines of 4 contact strips. Thus, during the drawing process, the material of the strips will be continuously joined (welded) at the point of their joint, i.e. along lines 4, the extent of which is equal to the width of lanes 2 and 3.

At the end of the stretching process, a hollow multi-faceted product is obtained with

longitudinal welds, the number of which is equal to the number of faces of the workpiece 1. The strength of the weld approaches the strength of the material to be printed. Although in the initial state the strips had different strengths, however, during the stretching process, less durable strips 2 strengthened and also approached in strength to stronger straps. This means In the circumferential direction the finished product will be of equal strength.

An example of a specific implementation method.

From sheet material (thickness

1.2 mm) D16M aluminum alloy (dg

 , 20 kgf / cm) cut down the workpiece in the form

correct octagon From the same

The material is made of strip width equal to the side of the octagon. D16T material (dg 42 kg / cm) is made into strips with a width equal to the side of the workpiece and subjected to tempering,

as a result, the material of the bands is even stronger (kg / cm). The strips are cleaned, for example, by chemical methods. K is welded by short sides of the strip to the workpiece, and the strips from annealed D16M alloy are welded to the blank zones forming rounded areas of the side surface of the product, and the strips from D16T alloy - to the blank zones. When a hollow tetrahedral prism was pulled out

- at the same time connection (welding by shift) strips on the long sides.

The proposed method allows to obtain hollow prismatic parts with a high height with longitudinal welded grooves, the strength of which approaches the strength of the main material and shortens their production time, since the subsequent (after stretching) welding operation is eliminated, as a result of which much

shrinking. 0

Claims (1)

Invention Formula A method of manufacturing hollow box-shaped products with rounded sections by attaching strips of their short sides to the facets of a multi-faceted sheet billet, stretching the obtained semi-finished product and connecting the strips along their long sides, characterized in that, with the aim of increasing productivity and improving the quality of the finished product, to the edges of the sheet blank, forming rounded areas of the side surface of the product during drawing, stripes of lesser strength than the strength of the strips attached to the edge m forming the flat sections of the article, and the connection strips along the long sides is carried out by welding shear during stretching.