镍基合金等离子堆焊层的组织和性能

采用光学显微镜、X射线衍射仪(XRD)、扫描电镜(SEM)和显微硬度计,研究了镍基合金等离子弧堆焊层的组织和性能。堆焊的基材为X65管线钢,焊丝是ERNiCrMo-3。研究结果表明,堆焊层由柱状晶和共晶组织组成,堆焊层中的柱状晶为γ固溶体,共晶组织为γ固溶体和Laves相(富含Mo、Nb);由腐蚀电化学测试可知,堆焊层的耐蚀性能随着堆焊电流的增大而减弱;氢致开裂试验结果表明,堆焊电流越大,越容易发生氢致裂纹;显微硬度测试结果表明,由基体至堆焊层显微硬度先升高后下降,熔合区硬度最高,可达310 HV以上。

The Structure and Property of the Nickel Base Alloy Plasma Surfacing Welding Layer

The structure and property of the nickel base alloy plasma arc surfacing layer were studied adopting optical microscope,X-ray diffractometer(XRD),scanning electron microscope(SEM) and microhardness tester.The layer substrate is the X65 pipeline steel;the welding wire is ERNiCrMo-3.The findings show that the surfacing layer consists of columnar crystal and eutectic.The columnar crystal in the overlay is the γ solid solution;the eutectic structure is the γ solid solution and Laves phase(containing rich Mo and Nb).It is known by corrosion electrochemistry testing that the corrosion-resistance performance of the layer weakens with the increase of the layer electric current.The hydrogen induced cracking experimental findings show that the greater the layer electric current,the more easily the hydrogen induced cracking takes place.The microhardness testing findings show that the microhardness first rises and then falls from the substrate to the layer with the maximum hardness in the fusion zone being over 310 HV.