A METHOD OF FORMING RIBS IN BIMETALLIC TUBES AND A RIBBED TUBE FORMED BY THE METHOD

摘要

A method of forming ribs on bimetallic tubes, in which initial compressive stress is introduced in the external tube (2), the roughness of the ends of the internal tubes (1) is increased, and after placing the internal tube (1) in the external tube (2), the ends of the external tube are clamped on segments (3, 4) of the internal tube (1) of increased roughness with simultaneous axial displacement of a part of the material of the external tube of a quantity adequate to introduce comressive stresses of a required quantity. In the tube thus prepared ribs are formed. It is preferable if at least one end of the external tube (2) is formed conically during clamping.