15CrMo钢多层堆焊过程中热影响区的组织演化行为及其对接头硬度的影响  

Microstructure Evolution of Heat Affected Zone of 15CrMo Steel during Multi-layer Welding and Its Influence on Hardness Distribution of Welded Joint

作　　者：冯琳杰[1] 吕品正[2] 赵永明 张巍 刘福广[2] 葛军[1] 杨二娟[2] 米紫昊[2] 王艳松 FENG Linjie;LYU Pinzheng;ZHAO Yongming;ZHANG Wei;LIU Fuguang;GE Jun;YANG Erjuan;MI Zihao;WANG Yansong(Huaneng Pingliang Power Generation Co.,Ltd.,Pingliang 744000,China;Xi'an Thermal Power Research Institute Co.,Ltd.,Xi'an 710032,China;China Nuclear Power Operation Management Co.,Ltd.,Hangzhou 310051,China)

机构地区：[1]华能平凉发电有限责任公司,甘肃平凉744000 [2]西安热工研究院有限公司,陕西西安710032 [3]中核核电运行管理有限公司,浙江杭州310051

出　　处：《热加工工艺》2021年第11期67-70,共4页Hot Working Technology

摘　　要：采用同质焊条在15CrMo钢表面进行了不同层数的堆焊,采用光学显微镜和显微硬度计对堆焊层显微组织和硬度分布进行了研究,探讨了过热区高硬度魏氏组织的演化过程及其对接头硬度的影响。结果表明:1层堆焊后的热影响区形成了高于母材和焊缝硬度的高硬度区,特别是过热区粗大的魏氏组织存在使热影响区硬度高于母材200HV;在后续多层堆焊中过热区在持续的热输入下逐渐由粗大的魏氏组织转变为细小的等轴晶。当堆焊超过5层时,魏氏组织向等轴晶的转变全部完成,热影响区无明显的峰值硬度,其与焊缝区硬度基本持平而与母材区的硬度之差缩小至100 HV以内,整个焊接接头部位硬度小于280 HV,可为接头在免焊后热处理的塑韧性提供可靠保障。Multi-layer bead welding was carried out on the surface of 15 CrMo steel by using the homogeneous welding rod, and the microstructure and hardness distribution was investigated by optical microscope and Vickers hardness tester. The evolution process of Widmannstatten structure with high hardness in overheated zone and its influence on the hardness of the joint were discussed. The results show that, the high hardness zone whose hardness is higher than those of both base metal and weld zone forms in heat affected zone(HAZ) after welding one layer, and the harness of heat affected zone is 200 HV higher than that of base metal due to the existence of Widmannstatten structure in overheated zone. The coarse Widmannstatten structure in overheated zone transfers to fine equiaxed grains gradually in subsequent multilayer surfacing, and the transformation is complete when the welding layer is higher than 5. There is no peak hardness in HAZ,which is almost the same with that of the welding zone and higher than that of base metal within 100 HV. The hardness of the welding joint is less than 280 HV, and it can provide reliable guarantee for the plastic toughness of the joint without postweld heat treatment.

关 键 词：多层焊接 热影响区 显微组织 显微硬度 

分 类 号：TG455[金属学及工艺—焊接]