WC-TiC-Ni/304不锈钢MIG焊缝界面碳化钨溶解特征研究  

WC Dissolution Behavior of As-Welded WC-TiC-Ni/304 Stainless Steel Joint Using MIG Welding

作　　者：曹晓莲[1] 徐培全[2] 马丁[1] 于香苑 李伟[1] 

机构地区：[1]上海工程技术大学材料工程学院,上海201620 [2]上海工程技术大学材料工程学院激光研究所,上海201620

出　　处：《稀有金属》2015年第10期870-876,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51105240);上海市曙光计划项目(13SG54);上海工程技术大学研究生科研创新项目(13KY0503)资助

摘　　要：以Φ1.2 mm纯Ni焊丝为填充金属,母材硬质合金侧开坡口或不开坡口,利用熔化极惰性气体保护焊(MIG)弧焊机器人实现了低粘结相WC-TiC-Ni系硬质合金与304不锈钢的异质连接。利用光学显微镜(OM)、扫描电镜(SEM)和能谱仪(EDS)以及电子探针(EPMA)研究了焊缝组织、形貌及界面元素扩散。讨论了接头硬质合金侧界面碳化钨溶解特征、异常晶粒长大(AGG)特征及影响因素。结果表明:采用该焊接方法在最佳焊接参数条件下:焊接速度v=45 cm·min-1,送丝速度v'=2.0 m·min-1,电压设定值18 V,保护气体流量15.8 L·min-1,单边开30°坡口,可以获得具有良好冶金结合的焊接接头,而且单边开坡口不留间隙较不开坡口留间隙的焊接效果好;在硬质合金侧界面区,与无填充焊接相比,焊缝中碳化钨溶解量很少;发现碳化钨稀疏层和η相层,通过硬质合金→致密(WC,TiC)/Ni→稀疏(WC,TiC)/Ni(母材中Ni和焊缝中Ni)→η相层实现硬质合金与钢的冶金结合。As-welded joint of low binder WC-TiC-Ni cemented carbide and 304 stainless steel was obtained with 1.2 mm nickel fill- er metal by metal inert-gas welding （MIG） robotic welding. Microstrueture, morphology and element diffusion were investigated using optical microscope （OM） , scanning electron microscope （SEM） and electron probe micro analyzer （EPMA）. On the basis, WC dis- solution and abnormal grain growth （AGG） in the region near cemented carbide/weld interface were discussed, and their influence fac- tors were also discussed. The results indicated that ： （ 1 ） well-metallurgical as-welded joints of cemented carbide and 304 stainless steel could be obtained using the following optimum welding parameters： welding velocity v = 45 cm a·min-l, wire feed rate v＇ = 2.0 m.min-l , voltage of 18 V, and shielding gas flow of 15.8 L·min-l ; in addition, without gap was recommended; （2） in contrast with as-welded joint without filler metals, the amount of WC dissolution near WC-TiC-Ni/weld interface was much less. In addition, non- density WC layer and η phase layer were also observed. Metallurgy bonding could be realized by cemented carbide→dense （ WC, TiC）/Ni→non-density （ WC ,TiC）/Ni→ phase layer.

关 键 词：硬质合金 熔化极惰性气体保护焊(MIG) 碳化钨溶解 异常晶粒长大 

分 类 号：TG146.41[一般工业技术—材料科学与工程]