扩径力与扩径行程的主要影响因素和计算方法

Calculating method and main influence factors of expanding force and expanding stroke

机械扩径是现代管线钢管制造方法的一项关键技术 ,包括扩径工艺和扩径装备两个方面。扩径力和扩径行程是机械扩径工艺的两个主要参数 ,也是开发机械扩径装备的重要依据。由于缺乏对机械扩径工艺的系统研究 ,准确计算扩径力和合理确定扩径行程 ,已经成为制约我国管线钢管制造技术发展和进步的主要技术障碍之一。本文针对现有扩径力计算方法的不足 ,在考虑变形程度及刚端影响的基础上 ,提出了一个新的扩径力计算公式 ;并且基于管坯的扩径过程可分为整圆和扩圆两个变形阶段的特征 ,分别给出了整圆、扩圆阶段的行程计算公式。此外 ,本文还通过实验与数值模拟相结合的方法 。

The mechanical expanding process is a key technique of cylindric products.The expanding force and stroke are main parameters of mechanical expanding process.They are also the important parameters for designing the expanding devices.Since the research of expanding technique is absent,the present methods for calculating the expanding force and stroke are not precision enough.In the paper,a new expanding force algorithm is given out considering the effects of deformation and stiffness end.And it is pointed out that the expanding stroke should be divided into two phases.In the first phase the tube section is changed to circle from ellipse,and in the second phase,the radius of tube is expanded.The stroke algorithms of two phases are also given out.The calculating results of expanding force and expanding stroke are compared with testing and simulation results.It is showed that the new algorithms are of higher precision.