Effect of Bead Overlapping on the Microstructure and Mechanical Properties of CoCrWC Alloy Coatings

In order to protect industrial components, cobalt base alloys are applied as hardfacing material through welding techniques. A large number of papers have shown that controlling the chemical composition is a key point regarding the wear and corrosion resistance of coatings. This paper investigated the effect of bead overlapping on the microstructure and properties of CoCrWC alloy coatings. Mechanical properties were determined by hardness, sliding wear and microtensile tests. Bead overlapping reduces dilution during the previous bead melting, which in turn induces lower iron content. From the second bead on, an increase in the amount of interdendritic carbides and solid solution alloying was verified, accounting for the higher mechanical properties of the coatings.

为保护工业零部件，钴基合金（cobalt base alloys）常通过焊接工艺作为堆焊材料使用。大量研究表明，调控化学成分是影响涂层耐磨耐蚀性能的关键所在。本文针对熔道搭接率对CoCrWC合金涂层微观组织与性能的影响展开了研究。通过硬度测试、滑动磨损试验及微拉伸试验测定了其力学性能。熔道搭接可降低前一道熔道重熔时的稀释率，进而使涂层中铁元素含量降低。自第二道熔道起，涂层内的晶间碳化物数量与固溶合金化程度均有所提升，这也是涂层力学性能得以提升的原因。