Taper Drawing of Non-Circular Steel Tubes by Dieless Eorming

点击翻译按钮获取中文摘要

It is impossible to give tapered drawing deformation in longitudinal direction for non-circular steel tubes using tools and dies, at the present technological knowledge and know-how. In this project, a new method for making tapered tubes having various cross-sectional shapes has been developed, combined with the techniques of roll forming and dieless forming.The following results are obtained from the fundamental research work and some problems for industrial avplication are also discussed :(1) Using the experimental sets of an induction heating device (max. power of 3 Kw, frequency of 2 MHz) and an Instron testing machine of 5 tons, square shaped steel tubes (21 x 21 mm, wall thickness 1.2 - 2.1 mm) were drawn for obtaining tapered tubes under various heating, cooling and/or deformation conditions ; a precise drwing can be conducted within the error of <plus-minus> 0.1 % in a taper angl(2) Suitable conditions of dieless drawing were investigated experimentally and theoretically.(3) A basical design of a proto type dieless drawing machine having a heating ability of 60 Kw and a pulling device of 50 tonf has been conducted, and the possibility of industrial application of this new process was confirmed.