焊接方法对奥氏体不锈钢焊接接头低温冲击性能的影响

Effect of welding methods on low temperature impact properties of austenitic stainless steel welded joints

为了研究奥氏体不锈钢焊接接头的低温冲击性能对低温压力容器的安全性影响,本文通过-196℃的低温冲击试验,对比研究了钨极气体保护焊(GTAW)、熔化极气体保护电弧焊(GMAW)、埋弧焊(SAW)3种焊接方法对S30408和S31608两种奥氏体不锈钢焊接接头低温冲击性能的影响。对于S30408焊接接头,热影响区的低温冲击性能小于母材与焊缝区,成为薄弱位置;3种焊接方法中,GTAW获得的焊接接头在热影响区的冲击性能处于最优水平。对于S31608焊接接头的低温冲击性能,焊缝、热影响区与母材的差异较小;3种焊接方法中,SAW获得的焊接接头在冲击吸收能量上与母材结果相近,能够获得焊接接头较好的综合冲击性能。通过对比不同焊接工艺下焊接接头断口形貌特征表明,焊接接头不同区域冲击断口形貌特征与低温冲击性能的结果相吻合。本文研究工作对于奥氏体不锈钢低温压力容器焊接工艺的选择具有参考意义。

To investigate the impact of low temperature impact performance of austenitic stainless steel welded joint on the safety of low temperature pressure vessels.The effects of three welding methods,GTAW,GMAW and SAW,on the low temperature impact performance of S30408 and S31608 austenitic stainless steel joints were studied by low temperature impact test at-196℃.For S30408 welded joint,the low temperature impact performance parameter of the heat affected zone is smaller than that of the base metal and weld zone,which becomes the weak position.Among the three welding methods,the impact performance parameters of welded joint obtained by GTAW are at the optimal level in the heat affected zone.For the low temperature impact performance of S31608 welded joint,the difference between weld,heat affected zone and base metal is small.Among the three welding methods,the result of the welded joint by SAW is similar to that of the base metal in terms of impact absorption energy,and better comprehensive impact performance of the welded joint can be obtained.The comparison of fracture morphologies of welded joints under different welding processes shows that the impact fracture morphologies of welded joints in different regions are consistent with the results of low temperature impact parameters.The research work provides a reference for the selection of welding method of low temperature austenitic stainless steel pressure vessel.