316L/X65 clad pipe was welded by GTAW and SMAW.In order to analyze the welding technology of clad pipe,hardness,tensile strength and impact toughness test of 316L/X65 weld joints were carried out.Micro-structure and chemical composition of weld joints were investigated by microscope,SEM,EDS.The corrosion resis-tance of weld joints was also researched by electrochemical experiment.The results show that the welding seam of clad pipe consists of carbon steel layer,diffusion layer,transition layer and stainless steel layer.The carbon steel layer is characterized by Acicular Ferrite,and diffusion layer is mainly consisted by Martensite.Ferrite is distributed on Aus-tensite boundary like worm or skeleton in transition layer and stainless steel layer.Under the experiment parameters, the stainless steel layer welding seam is influenced little by carbon steel layer,and it has the same chemical composi-tion with base material,but the corrosion resistance of weld seam decrease slightly.Weld joints show fine mechanical properties.%采用手工钨极氩弧焊和电弧焊实现了316L/X65双合金复合管的对接焊接.为了研究复合管的焊接工艺,对焊接接头进行了硬度、拉伸和冲击测试,利用光学显微镜、扫描电镜和能谱仪分析了接头的微观结构和成分特点,并对接头进行了电化学实验.结果表明:复合管焊缝由碳钢层、扩散层、过渡层和不锈钢层组成,碳钢层主要为针状铁素体,扩散层出现了马氏体组织,过渡层和不锈钢层焊缝中铁素体呈骨架或蠕虫状分布在奥氏体晶界;本实验焊接工艺下,覆层未受到碳钢层的稀释,化学成分与母材基本一致,但耐蚀性略有降低;焊接接头各项力学性能良好.
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