将核电厂水池覆面用S30403、S32101和S32205不锈钢焊接结构件在含SO^2-₄及Cl^-的硼酸溶液中腐蚀6个月,对比研究了3种不锈钢结构件的耐腐蚀性能并分析了腐蚀机理。结果表明:S32205不锈钢结构件发生均匀腐蚀,表面腐蚀产物较少,腐蚀程度较轻;S32101不锈钢结构件发生选择性腐蚀,出现较深的点蚀坑,点蚀坑内存在蓝绿色腐蚀产物;S30403不锈钢结构件发生应力腐蚀开裂,裂纹断口呈现解理断裂形貌,腐蚀最为严重。S32101不锈钢结构件由于铁素体相和奥氏体相的电位差以及铁素体中铬含量偏低等因素而发生铁素体相的选择性腐蚀;单相奥氏体S30403不锈钢结构件由于对Cl^-敏感并存在较高残余应力,因此无法形成两相协同作用而导致应力腐蚀开裂以及裂纹的快速扩展。

S30403, S32101 and S32205 stainless steel structural parts for nuclear power plant pool cladding were corroded in a boric acid solution containing SO^2-₄ and Cl^- for six months. The corrosion resistance of the three stainless steel structural parts was studied comparatively and the corrosion mechanisms were analyzed. The results show that the S32205 stainless steel structural part had uniform corrosion and less surface corrosion products, indicating the corrosion degree was slight. The selective corrosion of the S32101 stainless steel structural part occurred, and deep corrosion pits appeared. Blue-green corrosion products were found in the corrosion pits. Stress corrosion cracking occurred in the S30403 stainless steel structural parts, and the crack fracture showed cleavage fracture morphology, indicating the corrosion was the most serious. The selective corrosion of ferrite phases occurred in the S32101 stainless steel structural part due to the potential differences between ferrite phase and austenite phase and the low chromium content in ferrite. The single-phase austenitic S30403 stainless steel structural part was sensitive to Cl^-, had high residual stresses, and could not form a two-phase synergy, resulting in stress corrosion cracking and fast crack propagation.