电弧功率对MIG电弧增材制造316L奥氏体不锈钢组织及力学性能的影响  

Effect of arc power on microstructure and mechanical properties of austenitic stainless steel 316L fabricated by high efficient arc additive manufacturing

作　　者：陈晓晖 张述泉[1] 冉先喆[1] 黄正[1] CHEN Xiaohui;ZHANG Shuquan;RAN Xianzhe;HUANG Zheng(National Engineering Laboratory of Additive Manufacturing for Large Metallic,Components and Engineering Research Center,Beihang University,Beijing,100191,China;AECC Shanghai Commercial Aircraft Engine Manufacturing Co.,Ltd.,Shanghai,201306,China)

机构地区：[1]北京航空航天大学,大型金属构件增材制造国家工程试验室,北京100191 [2]中国航发上海商用航空发动机制造有限责任公司,上海201306

出　　处：《焊接学报》2020年第5期42-49,I0003,I0004,共10页Transactions of The China Welding Institution

基　　金：国家重点研发计划(2018YFB1105800);国家自然科学青年基金项目(51901010);中国铁路总公司重大课题资助(2017G003-C).

摘　　要：采用大功率MIG电弧热源熔化沉积316L奥氏体不锈钢金属焊丝制备试样,研究电弧功率对成形试样组织、力学性能以及断裂行为的影响并分析其机理,为高效、低成本电弧增材制造大型金属构件提供技术基础和理论依据.结果表明,大功率MIG电弧增材制造316L奥氏体不锈钢内部形成柱状晶并生成δ相和σ相呈蠕虫状分布在γ基体中.δ相分布在晶内和晶界起强化作用.随着电弧功率从3763 W增加8400 W,316L试样晶粒尺寸变大,δ相含量减少而σ相含量增加,使得材料抗拉强度从578 MPa降低到533 MPa,屈服强度从310 MPa降低到235 MPa,断后伸长率从53%降低到44%,断面收缩率从67%下降到60%.当电弧功率增加到8400 W时,在晶界上形成较多的σ相,试样断裂模式由较低功率时的穿晶韧窝断裂转变为沿晶韧窝断裂.The austenitic stainless steel 316 L was fabricated by high power MIG arc additive manufacturing and its microstructure evolution,mechanical properties and fracture behavior were investigated.Results show that there are columnar grains forming in the MIG arc additive manufacturing 316 L.The microstructure consists of vermicularδandσphases withinγmatrix.Theδdistributed both at grain boundaries and in the grains can strengthen the steel.With the arc power increasing from 3763 W to 8400 W,δphases decrease andσphases increase,as well as grain size increases.That leads to the ultimate tensile strength decrease from578 MPa to 533 MPa,yield strength decrease from 310 MPa to235 MPa,elongation decrease from 53%to 44%,reduction of area decrease from 67%to 60%.A pronounced feature is that the fracture type transfers from trans-granular dimple fracture to inter-granular dimpled fracture at the arc power of 8400 W.

关 键 词：增材制造 316L奥氏体不锈钢 显微组织 力学性能 

分 类 号：TG444[金属学及工艺—焊接]