316H堆焊UNS N10003合金参数优化、组织和硬度的研究  

Investigation on microstructure and hardness of UNS N10003 weld cladding on 316H with optimization of process parameters

作　　者：杨飞 黎超文[2] 李志军[2] 蒋力[2] 叶祥熙[2] 刘芳[1] YANG Fei;LI Chaowen;LI Zhijun;JIANG Li;YE Xiangxi;LIU Fang(School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Institule of Applied physics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]上海理工大学材料科学与工程学院,上海200093 [2]中国科学院上海应用物理研究所,上海201800

出　　处：《材料科学与工艺》2020年第2期1-8,共8页Materials Science and Technology

基　　金：上海自然科学基金(17ZR1436700);国家重点研究发展计划(2016YFB0700404,2017YFA0402803);国家自然科学基金(51371188,51671122,5161154,51601213,51501216);中国科学院战略重点研究计划(XDA02004210,XDA02004220和XDA02020400)和上海航海项目(16YF1414300);上海人才发展基金(201650).

摘　　要：研究异种合金焊接可以降低熔盐堆结构材料的成本并确保其安全性,本文采用钨极氩弧焊(GTAW)工艺,在316H不锈钢表面堆焊一层耐高温熔盐腐蚀的UNS N10003合金,优化了焊接工艺参数,通过光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、维氏硬度计等研究了堆焊层及界面的形貌、组织和硬度,为进一步研究多层、多道堆焊提供理论依据。研究结果表明:当电流一定时,稀释率随送丝速度的增加而减小,堆焊层高度随送丝速度的增加而增加,当送丝速度一定时,改变电流大小,堆焊层高度的变化范围为0.2~0.5 mm。堆焊层界面处可以细分为对流混合区(WM)、非对流混合区(UZ)和热影响基体区(BM)。堆焊层主要为奥氏体组织,在WM区有大量富Mo的M2C碳化物析出,UZ区的析出相主要是δ铁素体;316H基体区和WM区硬度分别为(160±10)HV和(202±11)HV,在γ基体的枝晶界上分布着尺寸细小的骨架状碳化物导致WM区硬度升高。Studying dissimilar alloy welding can reduce cost and ensure the safety of the molten salt reactor structural material.In this work,a cladding layer of UNS N10003 alloy which is resistant to the corrosion of molten salts was deposited on 316H stainless steel substrate using Gas Tungsten Arc Weld(GTAW)process.The welding parameters were optimized.The microstructure and hardness of the cladding layer and cladding-matrix interface were systematically characterized by optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Vickers hardness tester.It provides a theoretical basis for further research on multi-layer and multi-channel surfacing.The results show when the current was constant,the dilution rate decreased with the increase of the wire feeding,but the layer height increased with the increase of the wire feeding speed.When the wire feeding speed was constant,the layer height varied from 0.2 mm to 0.5 mm with the changing of current.The cladding interface was divided into welding zone(WZ),unmixed zone(UZ),and base material(BM).The microstructure in surfacing layer is mainly austenite.The eutectic carbide of M2C type with molybdenum was precipitated in WZ and a fewδ-ferrite precipitates could be found in UZ.The hardness of the cladding layer was relatively uniform and the hardness of UZ reached(202±11)HV,and the hardness of BM was(160±10)HV.The greater hardness of the cladding layer should be caused by the numerous tiny carbides distributed in the dendrite boundaries.

关 键 词：堆焊层 稀释率 参数优化 微观组织 316H奥氏体不锈钢 UNS N10003高温镍基合金 

分 类 号：TG455[金属学及工艺—焊接]