SU965558A1 - Method of producing welded thin wall curvilinear tubes - Google Patents

Description

(64) METHOD OF MANUFACTURING OF WELDED THIN-WALL CRIMINAL LINE PIPES

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The invention relates to the processing of metals by pressure and can be used in the manufacture of high-precision welded pipes with a variable radius of curvature of high-strength and low-plastic materials, for example, titanium 5 dplavov.

A known method for producing welded thin-walled curvilinear pipes from high-strength and low-ductile materials, including forming a tubular billet from a sheet of metal, welding its longitudinal butt, filling the inner cavity of the pipe with a suitable filler, bending the pipe by pushing the billet through a die, removing the filler and heat treating the pipe, In this case, alloy 1 is used as the 15 filler.

A disadvantage of the known method is the great laboriousness of manufacturing pipes associated with performing an editing and calibration operation to eliminate the pipe ovality before bending caused by the pipe leads during welding butt.

Closest to the proposed invention is the way in which

the tube blank is molded, the longitudinal joint is welded, filled with filler, bent and the filler 2 is removed.

The disadvantage of this method is the possibility of warping the pipe when welding a longitudinal joint.

The purpose of the invention is to reduce the labor intensity and improve the quality of manufacturing pipes from high-strength and low-ductile materials.

The goal is achieved in that the method of producing welded thin-walled curvilinear pipes, consisting in forming a tubular billet from a sheet of metal, welding its longitudinal butt, inserting a cylindrical insert into the internal cavity of a pipe, bending the pipe, removing the insert and heat treating the pipe, inserts from material, the melting point of which is in the temperature range of heat treatment of the billet material, and the billet is introduced before welding.

During the welding process, a seam shrinkage occurs. As a result, the pipe tightly encloses the insert and is calibrated. In turn, this makes it possible to produce

pipe bending on less complex equipment without the use of devices to prevent the extrusion of the filler from the pipe cavity. In addition, the removal of the filler is combined with the TepiMO pipe processing operation, since the melting point of the insert material is in the temperature range of the heat treatment of the billet material.

The method is implemented as follows.

Example. From the titanium sheet of the brand OT4-1 with dimensions of 40X314-0.2X1 mm and the temperature of heat treatment (annealing) of 640-660 ° C, a pipe billet was formed on the forming tool. A hollow cylindrical insert of an aluminum alloy of the AM brand with a wall thickness of 3 mm, a length of 400 mm, an outer diameter of 1 mm and a melting point of 654 ° C was installed in the molded billet. The longitudinal joint of the pipe billet was connected by argon-arc welding. After that, the titanium pipe was bent with an insert inside it, by rolling a roller around the stationary segment with simultaneous insertion of a mandrel into the insert.

After bending the process, the pipe was heated to 660 ° С, the insert melted and was removed from the pipe cavity. When the insert was smelted, it was heat treated. Heat treatment time was 45 minutes. In the process of bending, the aluminum insert gave the titanium pipe stability, promoted uniform distribution of pressure from the roller and

mandrel and thereby prevented the formation of corrugations, folds and cracks in places of pipe bending. During heat treatment, the warping of the titanium pipe did not occur, since the insert melted after the internal strains in the pipe, due to its heating, were relaxed.

Compared with the known method, the manufacture of pipes by the proposed method reduces the labor intensity twice.

Claims (2)

1. USSR author's certificate number 454072, cl. In 21 D 9/12, 1970. 2. The patent of France No. 2162545, cl. B 21 D 9/00, 08.24.73 (prototype).