热处理工艺对双相不锈钢S32101焊接接头力学性能与微观组织的影响

Effect of Heat Treatment Process on Mechanical Properties and Microstructure of Duplex Stainless Steel S32101 Welded Joints

采用E2209-15焊条对S32101双相不锈钢进行了对接式焊接,并对焊件进行了不同工艺的焊后处理,研究了焊后固溶处理对焊接接头低温冲击性能与微观组织的影响。研究结果表明:1050℃固溶处理铁素体含量最高,有良好的低温冲击韧性,冲击断口上韧窝小而密集,呈纤维网格状;焊后不固溶处理或固溶处理温度过低,焊缝区和热影响区会有富铬的有害沉淀相析出于晶界,主要成分是Cr2N,其周围为贫Cr的二次奥氏体,相界面不清晰,相比例失衡,降低了冲击韧性。1050℃固溶处理后有害相重新溶解到基体中,有害相被消除,相界面清晰。

Butt welding of the S32101 duplex stainless steel with E2209-15 electrode was carried out,and the weldments were postweld treated with different processes. The effect of postweld solution treatment on the low temperature impact properties and microstructure of the welded joint was studied. The results show the content of ferrite is the highest when the temperature of solution treatment is 1050℃. The low temperature impact toughness is good, and the dimples on the impact fracture surface are small and dense, showing fibrous mesh shape. The rich chromium harmful precipitation phase precipitates at grain boundary in weld zone and heat-affected zone when the postweld solution treatment isn’t carried out or the temperature of solution treatment is too low. The main component is Cr2N, which is surrounded by secondary austenite with poor Cr. The phase interface is not clear, the phase proportion is unbalanced, and the impact toughness reduces. The harmful phase dissolves into the matrix, the harmful phase is eliminated, and the phase interface is clear after 1050 ℃ solid solution treatment.