Taper Drawing of Non-Circular Steel Tubes by Dieless Eorming

在目前的技术知识和技术诀窍下，用工具和模具无法给出非圆钢管纵向的锥形拉深变形。本课题将滚压成形技术与无模成形技术相结合，开发了一种生产各种截面形状的锥形管材的新方法。从基础性研究工作中获得了以下结果，并讨论了工业应用中的一些问题：(1)利用感应加热装置的实验台(MAX。功率3千瓦，频率2 MHz)和Instron试验机5吨，方钢管(21×21 mm，壁厚1.2-2.1 mm)在不同的加热、冷却和/或变形条件下拉伸得到锥形管，可在&lt；正负&gt的误差范围内进行精密钻孔；(2)从实验和理论上探讨了无模拉伸的适宜条件。(3)对加热能力为60KW、拉拔装置为50tf的原型无模拉丝机进行了基本设计，证实了该新工艺工业化应用的可能性。

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.