基于铸钢堆焊用铁基高合金焊材的焊后热处理研究  

Study on Cast Steel Postweld Heat Hreatment with Fe-based High-alloy Flux-cored Wire

作　　者：张雪晖[1] 黄芳[1] 

机构地区：[1]浙江工业职业技术学院,浙江绍兴312000

出　　处：《热加工工艺》2016年第21期220-223,共4页Hot Working Technology

基　　金：浙江省教育厅访问工程师项目(FG2014115)

摘　　要：采用Fe-Cr-Ni系药芯焊丝在ZG25CrNiMn基体表面进行埋弧堆焊,焊后分别进行空冷及200、300、400、500、600℃不同温度回火处理。通过金相显微观察、硬度检测、摩擦试验以及冲击试验和SEM扫描等试验方法分析了焊后不同处理对堆焊层组织、硬度、耐磨性及断裂机理的影响规律。结果表明:焊后采取不同处理,堆焊层的组织形貌、硬度、耐磨性以及断口形貌存在较大差异。焊后空冷条件下,堆焊层主要为粗大的片状马氏体组织,硬度较高,耐磨性及冲击韧性较低,断裂面出现较多的大面积平整断裂面,表现为明显的脆性断裂。焊后200℃低温回火条件下,组织和力学性能变化较小,当回火温度超过200℃时,随着回火温度的升高,堆焊层中原有的粗大片状马氏体逐渐减少,细小的板条状回火马氏体逐渐增多,硬度逐渐降低,耐磨性逐渐提高,同时堆焊层的韧性逐渐得到改善,断裂面中逐渐出现一定数量的较小较深的断裂韧窝。当回火温度达到500℃时,堆焊层的硬度降低,耐磨性较高,断裂面的断裂韧窝较多,当回火温度达到600℃时,堆焊层主要表现为细小的粒状回火索氏体,耐磨性降低。Submerged arc surfacing on the surface of ZG25CrNiMn substrate was carded out with Fe-Cr-Ni series fluxcored wire. Afrer welding, air cooling and tempering treatment with temperature of 200, 300, 400, 500, 600 ℃ were carriedout respectively. The effects of different welding processes on microstructure, hardness, wear resistance and fracturemechanism of surfacing layer were analyzed by microstructure observation, hardness test, friction test and impact test andSEM scanning and other test methods. The results show that heat treatment greatly influences the microstructure, hardnessdistribution, wear resistance and fraction morphology of welding layer. Under air cooling condition after welding, themicrostructure of welding layer is mainly coarse flake martensite with high hardness, low wear resistance and low impacttoughness. The fracture surface is mainly smooth and flat area, which shows obvious brittle fracture. Under 200 ℃ temperingcondition after welding, the microstructure and the mechanical properties show slight improvement. With higher temperingtemperature above 200 ℃, some coarse plate martensite reduces gradually, while fine tempered lath martensite increasesgradually, hardness reduces and wear resistance improves. The toughness improves and some small deep dimples appear onthe fracture siface. When tempering temperature reaches 500 ℃, the hardness of the welding layer decrease, the wearresistance is excellent and dimples are plentiful. When tempering temperature reaches 600 ℃, the microstructure transforms togranular tempered sorbite and the wear resistance reduces.

关 键 词：ZG25Cr Ni Mn Fe-Cr-Ni系药芯焊丝 堆焊 焊后热处理 

分 类 号：TG441.8[金属学及工艺—焊接]