焊后热处理对5CrNiMo钢堆焊熔合区组织及韧性影响  

Effect of Postweld Heat Treatment on Microstructure and Toughness of 5CrNiMo Steel Surfacing Welding Fusion Zone

作　　者：卜建荣[1] 徐君燕[2] 

机构地区：[1]浙江工业职业技术学院汽车学院,浙江绍兴31200 [2]浙江工业职业技术学院电气电子工程学院,浙江绍兴31200

出　　处：《热加工工艺》2015年第5期217-219,共3页Hot Working Technology

基　　金：浙江工业职业技术学院2013年科研项目(111000210920113165)

摘　　要：采用药芯焊丝对失效的5CrNiMo热锻模具表层进行堆焊,堆焊后分别进行空冷和400℃×4 h回火处理。利用金相显微镜、显微硬度计及扫描电镜对比分析焊后不同处理条件下的熔合区组织、硬度梯度及冲击韧性。试验结果表明:焊后空冷和焊后回火熔合区组织和性能出现较大的差异性,焊后空冷条件下焊接热影响区出现大量的魏氏组织,熔覆层为大量的片状马氏体和板条马氏体,且熔合区硬度梯度较大;焊后回火处理的焊接热影响区魏氏组织消失,同时熔覆层转变为力学性能较好的板条回火马氏体和回火屈氏体,熔合区断面出现大量较小的韧窝,韧性改善,并且熔合线两侧的最大硬度梯度降低了约60 HV。Adopting flux-cored wire for the welding of the failure of 5CrNiMo hot forging die surface, after welding, air cooling and 400℃×4h tempering treatment was carried out, respectively. The microstructure,microhardness gradient and impact toughness of fusion zone under different conditions after welding were studied by microscope, microhardness meter and SEM fusion zone group. The results show that there are a large number of widmanstatten structure in heat affected zone, and a large amount of thick plate martensite in cladding layer .The microhardness gradient between substrate and the cladding layer is large under the condition of air cooling after welding. After tempering treatment, the widmanstatten structure in heat affected zone disappears, the mierostructure of cladding layer transforms into lath tempered martensite and temper troostite, a large number of smaller toughening appears in the fusion zone section, and the toughness improves. Meanwhile, the maximum hardness gradient on either side of the fusion line reduces about 80 HV.

关 键 词：堆焊 5CRNIMO钢 显微组织 硬度梯度 韧性 

分 类 号：TG455[金属学及工艺—焊接]