低浓度硼酸溶液水箱焊缝缺陷分析

Analysis of Weld Defect in Low Concentration Boric Acid Tank

采用光谱仪、扫描电镜及能谱分析等方法,对低浓度硼酸溶液水箱缺陷试样进行研究,结果表明,腐蚀产物中存在氯离子来源于钢衬里背面的保温材料;裂纹起源于加强板与钢衬里的接触缝隙腐蚀以及母材与保温材料接触点的点腐蚀;裂纹主要为穿晶裂纹且呈现树枝状扩展;低浓度硼酸溶液水箱焊缝缺陷原因为应力腐蚀,可采用双相不锈钢材料对缺陷进行修复。

The defect sample of low concentration of boric acid tank was studied by spectrometer,scanning electron microscopy and energy dispersive x-ray analysis.The results show that the chloride ion was detected in corrosion products,which derived from the thermal insulation material on the back of the steel lining.The crack mainly originated from the crevice corrosion of the reinforcing plate and the steel lining,the point corrosion of the parent metal and the thermal insulation material.The crack propagates in the form of transgranular,and the weld defect reason of low concentration of boric acid tank was stress corrosion.The defect can be repaired with duplex stainless steel.