高强钢22MnB5扭力梁热成形热力耦合数值模拟

Hot forming processing simulation of torsion beam of high strength steel 22MnB5

为了探究高强钢管22MnB5热气胀成形V型截面扭力梁的工艺,采用热力耦合数值模拟的方法研究了高温成形时扭力梁温度场、应力场、应变场、壁厚分布规律以及成形精度.研究发现:成形结束时,由于温度场分布的差异,各个区域材料流变性能不同,因此,最大主应力位于温度场较低区域,最大主应变位于温度场较高且膨胀量较大区域;随着试件初始温度的提高,成形后试件最低温度和最大减薄率均增大,成形精度提高;随着摩擦系数的增大,成形后试件最大减薄率增大.研究表明:当初始试件温度为850℃、摩擦系数为0.1、整形气压20 MPa时,成形后得到成形精度较高,最大减薄率为14%的试件,且成形后最低温度为499℃,高于马氏体开始转变温度.

To study the forming process of V-shape torsion beam using high strength steel tube 22MnB5 under the method of gas forming at elevated temperature,numerical simulation was carried out to analyze the temperature field,stress field,strain field,thickness distribution and form precision. Material flow stresses in different areas change because of difference of temperature distribution,so the max principal stress is located on the low temperature area and the max principal strain is located on the high temperature and high expansion rate area. With the raising of initial tube temperature,the lowest temperature and biggest thinning rate of formed torsion beam increase and the forming precision improves simultaneously. And with the raising of coefficient of friction,the biggest thinning rate of formed torsion beam increases. When the initial temperature is 850 ℃,the coefficient of friction is 0. 1,and the calibration pressure is 20 MPa,the reasonable pieces with high precision and low thinning rate of 14% can be obtained,and at the same time the lowest temperature is499 ℃ which is far higher than the beginning of martensitic transformation.