Cr涂层厚度对锆合金包壳GTAW焊缝组织与性能的影响分析

Influence of Thickness of Cr Coating on GTAW Welding's Microstructure and Property of Zircalloy Cladding Tube

研究了Cr涂层厚度对锆合金包壳GTAW接头组织和性能的影响,结果表明涂层明显降低焊缝的熔深,Cr元素非均匀熔入焊缝造成焊缝点状特征出现,且随涂层厚度增加而增多,当涂层厚度超过20μm后,涂层侧焊缝形成鱼骨状的共晶组织,并观察到沿晶间扩展的显微裂纹。水腐蚀下焊缝表面的富Cr层具有明显的裂纹和脱落倾向,熔于焊缝内的Cr元素则显著增加焊缝的硬度,当Cr涂层厚度为15μm时焊缝硬度最高,达到299 Hv,涂层厚度继续增加焊缝硬度出现降低趋势。

The influence of Cr coating's thickness on the microstructure and property of zircalloy tube's GTAW welding was studies in this paper,and the results indicated that Cr coating obviously decreased weld penetration,and the spotted characteristics caused by non-uniform distribution of Cr in weld,which increased with the increase of the Cr coating thickness.When the coating thickness exceeded 20μm,fish-bone eutectic was observed in the weld of the coating side,and the micro crack spreading along the intergranular was also seen.The Cr-riched welding surface showed obvious tendency to crack and shed under water corrosion condition,and element Cr in weld significantly increased the weld hardness.The weld hardness reached 299Hv when Cr coating thickness was 15μm,the hardness of weld decreased when the Cr thickness increased more.