机械振动焊接对残余应力的影响及机理分析

Effect of Mechanical Vibration Welding on Residual Stress and Its Mechanism Analysis

机械振动焊接是在振动调整残余应力技术基础上发展起来的一项焊接新技术。这种焊接新技术 ,不仅能提高焊接质量 ,改善焊接接头金相组织 ,提高接头金属的力学性能 ,而且能省去焊后调整残余应力的工序 ,从而缩短生产周期 ,降低生产成本 ,并将给焊接生产领域带来巨大的经济效益。试验选用压力容器常用钢 1 6MnR作为试验材料 ,采用机械振动焊接钢板与常规埋弧自动焊接钢板对比实验方法 ,通过残余应力测试和测试结果分析研究了机械振动焊接对残余应力的影响。结果表明 ,机械振动焊接可降低焊接残余应力 ;当频率、振幅 (激振力 )选取合适时 ,其降低效果更显著。而机械振动焊接降低残余应力的机理主要是由于机械振动使焊缝及周围的温度梯度减小和振动使晶粒细化。

Mechanical vibration welding is a new welding technology which was developed on the basis of vibration-stress-relief-technology. This new welding technology can improve welding quality, micro-structure of joint, mechanical properties of joint metal and save the process of adjusting residual stress after welding. Thus the production cycle is shortened and the production cost is lowered. So it can bring about huge economic benefits to welding production field. In test, steel 16MnR which is usually used for pressure vessel is chosen as test material. The method of contrast test between the steel plate welded by mechanical vibration welding and the one by ordinary SAW has been used to study the effect on the residual stress through residual stress testing and testing result analysis. The results show that mechanical vibration welding can reduce residual stress; the effect of reducing residual stress by vibration welding is even more notable when the frequency and amplitude (vibrated force) are chosen appropriately. The mechanism that mechanical vibration welding affected on residual stress mainly lies in that the mechanical vibration could make the temperature gradient in and around weld small, the grains fine and the distribution of microstructure uniform.