304不銹鋼焊縫在NaCl溶液中SCC的下限溫度

The Critical Temperature for The SCC of 304SS Weldments in Solutions of NaCl

摘要: 本文用慢應變速率實驗技術研究了304不銹鋼焊接接頭在NaCl溶液中的應力腐蝕行為。結果發現:該體系發生應力腐蝕存在一個界限溫度,NaCl濃度低于1.0mol/L時,界限溫度隨NaCl濃度的增加而下降;NaCl濃度高于1.0mol/L時,SCC的界限溫度在很寬NaCl濃度范圍內變化不大。并給出了該體系發生SCC的T°(C)-Cl^--SCC圖。焊接接頭的應力腐蝕發生在焊縫區,應力腐蝕裂紋是沿著奧氏體枝晶間的δ-鐵素體擴展的。

Abstract: The stress corrosion cracking of 304SS weldments in NaCl solutions has been shudied by SSRT technique.It was found that there exists a critical temperature for the SCC in this system.The cirtical temperature decreases with the increase of NaCl concentration when the concentration of NaCl is lower than 1.0mol/L, but it doesn't change much in a wide range of NaCl concentration when the concentration of NaCl is higher than 1.0mol/L.The diagram of T(℃)-Cl^--SCC has been given.For the weldment,SCC occurs in weld fusion zone and propagates along δ-ferrite phase between austenite dendrites.