由于Super304H钢管长期在其敏化温度450~850℃服役,易在晶界上析出 M23 C6,从而发生晶间腐蚀,导致其脆化进而造成爆管,采用电化学动电位再活化法(electrochemical potentiokinetic reactivation,EPR),结合扫描电镜研究了Super304H的焊缝、热影响区及母材的晶间腐蚀性能,分析敏化处理对其晶间腐蚀敏感性的影响。EPR实验结果表明未敏化处理的Super304H焊缝、热影响区及母材均无晶间腐蚀倾向；在650℃敏化5 h后,焊缝、热影响区及母材的再活化率均增加,其中焊缝的晶间腐蚀敏感性较低。扫描电镜结果表明热影响区及母材均发生了明显的晶间腐蚀。%It is easy to separate out M23 C6 on the crystal boundary for reason of Super304H steel tube working at its sensibili-zation temperature of 450~850 ℃ in the long term which may cause intergranular corrosion and result in embrittlement and tube burst. Combining scanning electron microscope,electrochemical potentiokinetic reactivation (EPR)was applied for studying welding joint,heat affected zone of Super304H and intergranular corrosion performance of the parent metal,ana-lyzing influence of sensibilization on sensitivity of intergranular corrosion. EPR experiment results indicate there is no inter-granular corrosion in Super304H welding joint,heat affected zone and the parent metal without sensitizing treatment. In ad-dition,after five hours of sensibilization at 650 ℃,reactivation rates of welding joint,heat affected zone and the parent metal all increase and sensitivity of intergranular corrosion of welding joint is lower. Scanning electron microscope result in-dicates that obvious intergranular corrosion occurs to heat affected zone and the parent metal.
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