SU837438A1 - Method of producing welder straight-seam tubes - Google Patents

Description

This invention relates to the manufacture of welded RECTUME tubes. Most effectively it can be used in the manufacture of alloyed and stainless pipes using argon-arc welding (ADF).

A known method of making welded RECTANGULAR pipes, concludes with a gradual transverse bending of the original strip into pipe billet 1

The disadvantage of this method is that when the tubular billet leaves the last forming stand, due to its elastic loading of the mesh with the edges of the billet, a significant gap is formed. As a result, tensile tangential stresses in the weld seam break the joint with the non-crystallized metal to form so-called or longitudinal cracks, which prevents an increase in the welding speed.

There is also known a method for producing welded SPRAY tubes in which the initial strip is pre-bent in the transverse direction and then molded along a radius smaller than the radius of the finished tube 2.

The disadvantage of the method is that in the process of alternately molding each half of the workpiece

radius, smaller radius of the finished pipe inevitably overlaps the edges of the pipe billet. Thus, it is necessary to refuse the traditional closed calibers with

split washer. As a result, in the process of alternate molding, the transverse displacement of the strip or the spiral twisting of the tube blank is unavoidable. This leads to

Different areas are formed in the left and right sides of the preform, which is the reason for the relative displacement of the edges in the weld zone. In addition, this drawback of the molding process complicates the necessary strict feeding of the edges of the tube stock under the burner of the welding unit.

The purpose of the invention is to improve the quality of welded pipes by reducing the gap between the edges of the tube blank, as well as eliminating the spiral twisting of the latter.

This goal is achieved by

that molding along a smaller radius

the radius of the finished pipe is carried out on the peripheral sections of the pipe billet with a length of 0.15-0.25 strip width, and the radius of the molding is taken to be 0.6-0.8 of the radius of the finished pipe.

In the manufacture of pipes using this method, due to the simultaneous molding of peripheral sections of the specified length by a radius smaller than the radius of the finished pipe, after the edge is springing, they come to the position most favorable for their high-quality welding, since the gap between the edges and the angle of convergence of the ends are minimal compared to by known methods. In addition, the possibility of using this method of forming in all or in most of the closed gauges of the cut. The washer eliminates the spiral twisting of the billet, thereby ensuring accurate edge placement under the torch of the ADS unit. When molding the peripheral sections in a section of more than 0.25 strip width or less than 0.6 of the radius of the finished pipe, these areas after elastic bending do not spring to the radius of the finished pipe, which leads to the welding of edges with their sagging inside the pipe. When these sections are formed less than 0.15 strip width or more than 0.8 of the radius of the finished pipe, the effect of this method is insignificant and differs little from the bulk process, when a significant gap occurs with edges and sharply increases the angle of convergence of the edges. Thus, it is necessary to limit the specified PLI to the limit.

In the drawing, a sequential change in the cross-section of the billet is shown during molding in this process.

The method is carried out as follows.

The initial strip is gradually bent (section 1-3), giving it the shape of a tubular billet. Then the peripheral areas with a length of E 0.150, 25 V (where B is the width of the strip) of a pre-bent tubular billet are simultaneously molded to a radius of 0.6-0.8, (where, the radius of the finished, welded pipe) With a curved edge inside the blank (section 4 ), After springing

tubular billet its edges are reduced, and then welded with the formation of a longitudinal seam (section 5).

Example 1. In the manufacture of pipes 0 102x2 mm, the peripheral sections with a length of E 48 mm (0.15 V) of the preformed pipe billet are bent at the same time with a radius of 35 mm (0.68 RC-p) with curved edges inside the billet.

Example 2. By production

0 pipes0102 2 mm peripheral areas 80 mm long (0.25 V) of the preformed pipe billet bend at the same time with a radius g 40 mm (0.8 R-fp) with bending edges

5 inside the workpiece.

The result is high quality pipes.

This method of manufacture is welded. compared with the best examples of the known methods, pipe quality can be improved when manufactured using the ADF method by simultaneously reducing the gap between the edges (i.e., elastic springing of pipe stocking) and the angle of convergence of the edges.

Claims (2)

1.VatkinYa.L. and others. Pipe production M., metallurgi; 1970, 0 s. 338-345. 2. USSR author's certificate No. 555931, cl. B 21 C 37/06, 1974 (prototype).