Cr涂层锆合金包壳管与端塞环缝焊接接头耐腐蚀性能研究

Study on Corrosion Resistance of Girth Gelding Joint of Cr-Coated Zirconium Alloy Cladding Tube and End Plug

采用压力电阻焊及TIG焊两种方式焊接无涂层/Cr涂层锆合金包壳管与端塞,研究其焊接接头组织和耐腐蚀性能。采用高压釜对焊接试样进行高温高压水腐蚀试验,采用SEM对焊接接头试样进行腐蚀后的外表面形貌表征以及对Cr涂层包壳管焊接接头试样进行纵截面形貌表征,采用EDS进行微区成分分析,采用金相显微镜观察接头试样纵截面显微组织。结果表明,当采用TIG焊对Cr涂层锆合金包壳管进行焊接时,焊接接头中出现了Cr与Zr两种金属的合金化现象,接头中存在较多的气孔和裂纹;而当采用压力电阻焊对Cr涂层锆合金包壳管进行焊接时,Cr涂层并没有对焊接接头产生负面影响,接头在保持良好焊接性能的同时,还具备了良好的抗高温水腐蚀性能。

Pressure resistance welding and TIG welding were used to weld the welding joint between the uncoated/Cr-coated zirconium alloy cladding tube and the end plug. The microstructure and corrosion resistance of the welded joint were evaluated. Testing corrosion property of welding specimen using high temperature and high pressure water. The surface morphology of the welded joint specimen after etching and the longitudinal section morphology of Cr coating cladding tube welded joint specimen were studied by means of SEM. The composition of the interface was identified by EDS. The longitudinal section microstructure of welded joint specimen was observed by using microscope. Results prove that when the zirconium alloy cladding tube with Cr coating was welded by TIG welding method, the alloying phenomenon of Cr and Zr metals appeared in the welded joint, and many pores and cracks appeared in the joint. However, the presence of Cr coating did not have a negative effect on the welded joints when using pressure resistance welding method, and the welded joints maintained good welding performance and had a good resistance to high temperature water corrosion.