超声喷丸对敏化后304奥氏体不锈钢应力腐蚀性能的影响

摘要

Through sensitization and ultrasonic peening, the 304 austenitic stainless steel was experimented and its stress corrosion was investigated.Through adopting metallographic examination, micro hardness, slow strain rate tensile test and micro fracture method with SEM, the impact of experimental sensitization process on the performance of the 304 austenitic stainless steel was analyzed.It is concluded that, the 304 austenitic stainless steel has a large number of carbides and the stress corrosion resistance decreases after the experi-ment.In the slow strain rate tensile test, the plastic section is shortened and the fracture surface expands along the grain boundary, and the plasticity decreases sharply.The surface hardness of 304 austenitic stainless steel can be improved, including the stress corrosion resistance through the ultrasonic peening.The experimental results prove that, applying the ultrasonic shot peening technology to material surface processing can effectively prevent cracking growth of intergranular corrosion and stress corrosion;and with the increasing of surface cov-erage of ultrasonic shot peening treatment, the stress corrosion resistance can be further improved.%对304奥氏体不锈钢进行了敏化试验与超声喷丸试验,并对其应力腐蚀性能进行研究.通过金相、微观硬度、慢应变速率拉神试验和SEM微观断口方法,分析敏化试验过程对304奥氏体不锈钢材料性能的影响.得出304奥氏体不锈钢在敏化试验后,材料晶间会析出大量碳化物且耐应力腐蚀性能下降的结论.慢应变速率拉伸试验中表现出塑性段缩短、断口沿晶界扩展、塑性大幅下降的现象.通过后续的超声喷丸处理可提升304奥氏体不锈钢的表面硬度,并使其抗应力腐蚀性能提高.试验证明了超声喷丸技术应用于材料表面可有效阻止晶间腐蚀及应力腐蚀裂纹扩展,且随着表面超声喷丸处理覆盖率的增大,材料抗应力腐蚀性能进一步提高.