SU145525A1 - Method of making shaped tubes - Google Patents

Description

Methods are known for making cold rolling profile tubes from a cylindrical billet with identical walls along the perimeter of the section.

The described method of making profiled tubes differs from the known ones in that the drawing is carried out from a billet having a circular opening with longitudinal ribs, and the main deformation is profiling with subsequent compression along the walls. This provides pipes with different wall thicknesses around the perimeter of the cross section.

FIG. 1 shows a blank with two longitudinal protrusions and a circular opening for obtaining a shaped pipe by the proposed method; in fig. 2 shows the shape of the change in pipe cross section when drawing a symmetric rectangular pipe; in fig. 3 shows the shape of the change in the pipe cross-section when receiving asymmetrical shaped pipes by the proposed method.

The manufacture of pipes with different wall thickness along the perimeter of the proposed method is carried out by shaping the pressed billet, followed by slight compression in the production of thick-walled pipes (2 mm and higher depending on the material of the tool and product) and significant compression when producing pipes with a wall thickness less than possible to obtain by pressing. The profiling consists of a combination of a series of consecutive alignment and mandrel passes. For example, when drawing symmetrical rectangular pipes with a rectangular opening, one is done without correction drawing - flattening 1 (see Fig. 2) and one finishing drawing on a short mandrel. When drawing a mandrel, the deformation process can be divided into several stages: reduction 2, deformation 3, walls and calibration 4. To reduce

force on the rod onravki last can be a floating type. The proposed method allows the manufacture of various pipes, both symmetrical in cross section (see Fig. 2) and asymmetrical, with unequal wall thickness along the perimeter and any hole configuration (see Fig. 3).

The Ukrainian Research and Development Pipe Institute notes the rationality of applying the proposed method for the manufacture of shaped tubes.

Subject invention

A method of manufacturing shaped pipes, characterized in that, in order to produce pipes with different wall thickness along the cross section, drawing is carried out from a blank having a rounded hole with longitudinal (one or several) ribs, and the main deformation will be profiling followed by compression along the walls .