低合金钢堆焊镍基合金接头中的宏观偏析研究  

Study on Macrosegregation in Welding Joint of Nickel-Based Alloy Overlay on Low Alloy Steel

作　　者：丁铭 鲁立[2] 张禹 丁永三 杨佳[2] 吕一仕[2] 李克俭[3] 蔡志鹏[3] DING Ming;LU Li;ZHANG Yu;DING Yongsan;YANG Jia;LYU Yishi;LI Kejian;CAI Zhipeng(National Energy Group Jianbi Power Plant,Zhenjiang 212006,China;Suzhou Nuclear Power Research Institute,Suzhou 215004,China;Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]国家能源集团谏壁发电厂,江苏镇江212006 [2]苏州热工研究院有限公司,江苏苏州215004 [3]清华大学机械工程系,北京100084

出　　处：《热加工工艺》2023年第15期55-58,共4页Hot Working Technology

基　　金：国家能源集团科技项目(GJNY-19-82)。

摘　　要：在T23低合金钢上堆焊了ERNi Cr-3镍基焊材,研究了低合金钢堆焊镍基合金接头中的宏观偏析特点及形成机理。利用光学显微镜、扫描电镜和电子背散射衍射仪(EBSD)等分析工具,对堆焊后接头焊接界面处的组织进行了表征。结果表明,宏观偏析主要发生在焊道交叠处,在靠近熔合线的焊缝中形成Fe含量较高且晶体结构与低合金钢母材一样的条带状组织。宏观偏析的形成主要与母材和焊材的液相线温度差异有关,镍基焊材液相线温度低于低合金钢母材导致在焊道交叠处的局部熔池温度低于母材液相线温度,熔化的母材对流进入该区域会因为过冷而快速凝固,从而导致宏观偏析。选用与母材液相线温度更接近的焊材、降低焊接热输入有利于减少宏观偏析的发生。ERNiCr-3 nickel-based alloy welding material was overlaid on the low alloy steel T23,and the macrosegregation characteristics and the formation mechanism in the welded joint were investigated.The structure of the welding interface after overlay welding was characterized by optical microscope(OM),scanning electron microscope(SEM)and electron backscatter diffraction(EBSD).The results show that macrosegregation mainly occurs at the overlapping region of weld beads,a band structure in the weld metal near the fusion line is formed with high Fe content and same crystal structure with the low alloy steel base metal.The formation of macrosegregation is mainly related to the liquidus temperature difference between the base metal and the filler material.Because the liquidus temperature of nickel-based filler material is lower than that of the low alloy steel base metal,the temperature of local molten pool at the overlapping region of weld beads is lower than the liquidus temperature of base metal.Hence,the molten base metal flows into the region by convection will quickly solidify due to undercooling,resulting in macrosegregation.Selecting filler material with similar liquidus temperature to that of the base metal and reducing the welding heat input will help to reduce the macrosegregation.

关 键 词：堆焊 异种金属焊接 低合金钢 镍基合金 宏观偏析 

分 类 号：TG455[金属学及工艺—焊接] TG401