310S不锈钢焊接接头高温力学性能及组织演变  

Mechanical Properties and Microstructure Evolution of 310S Austenitic Stainless Steel Welded Joint at High Temperature

作　　者：姜云禄 陈静[1,2] 阚盈[1,2] 吴昌忠[2] 陈怀宁 JIANG Yunlu;CHEN Jing;KAN Ying;WU Changzhong;CHEN Huaining(Key Laboratory of Nuclear Materials and Safety Assessment,Chinese Academy of Sciences,Shenyang 110016;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016)

机构地区：[1]中国科学院核用材料与安全评价重点实验室,沈阳110016 [2]中国科学院金属研究所,沈阳110016 [3]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《机械工程学报》2024年第12期250-258,共9页Journal of Mechanical Engineering

基　　金：中核集团领创科研资助项目。

摘　　要：耐热不锈钢是高放废液固化容器的理想材料,而焊接接头的高温性能和组织演化对固化容器的尺寸稳定性和服役安全具有重要影响。基于等离子弧焊接技术制备310S奥氏体不锈钢焊接接头,研究不同温度(室温~1100℃)对焊接接头拉伸性能的影响和分别在600℃和1100℃条件下焊接接头的蠕变性能。借助光学显微镜、扫描电镜、背散射电镜、透射电镜和拉伸试验机,对金相组织、断口形貌、相组成及元素分布和拉伸性能进行分析。结果表明:敏化温度附近材料的伸长率最低,拉伸断口出现较大空洞,随着温度升高至1100℃,断口表面出现氧化。焊接接头具有优异的抗高温蠕变性能,600℃蠕变试验后在母材区形成孪晶组织,1100℃蠕变后焊缝区铁素体消失,晶粒尺寸出现长大。高温和应力作用促进晶界处析出M23C6相,削弱晶界强度,裂纹在晶界处形核、长大和扩展,最终造成焊接接头出现沿晶断裂。研究成果为高放废液固化容器的服役安全提供参考,同时丰富了高放废液后处理的基础数据。Heat-resistant stainless steel is an ideal material for high level waste liquid solidified container,and the high temperature properties and microstructure evolution of welded joints have an important effect on dimensional stability and service safety for solidified container.The welding joint of 310S austenitic stainless steel is prepared by plasma arc welding technology.The influence of different temperatures(room temperature to 1100 C)on the tensile properties of the welded joint and the creep properties of the welded joint at 600 C and 1100 C are studied.The microstructure,fracture morphology,phase composition,element distribution and tensile properties are analyzed by means of optical microscope,scanning electron microscopy,electron back scatter diffraction,transmission electron microscopy and tensile testing machine.The results show that the elongation of the material is the lowest near the sensitization temperature,and large holes appear in the tensile fracture.With the temperature increasing to 1100 C,oxidation occurs on the fracture surface.The welded joint has excellent high temperature creep resistance.Twin microstructure is formed in the base metal zone after 600 C creep,ferrite disappears and grain size grows after 1100 C creep.The effects of high temperature and stress promote the precipitation of M23C phase at the grain boundary,which weakens the grain boundary strength.The cracks nucleate,grow and expand at the grain boundary,then finally cause the welded joints intergranular fracture.The research results provide reference for the safety of the high level waste liquid solidifying vessel and enrich the basic data of the high level waste liquid post-treatme.

关 键 词：310S不锈钢 焊接接头 高温力学性能 组织演变 蠕变 

分 类 号：TG444[金属学及工艺—焊接]