焊接速度对308L不锈钢CMT电弧增材制造薄壁件组织及性能的影响  

Effect of welding speed on microstructure and properties of 308L stainless steel CMT arc additive manufactured thin-walled parts

作　　者：李敬勇[1] 叶凡凡 徐育烺 钱鹏 LI Jing-yong;YE Fan-fan;XU Yu-lang;QIAN Peng(Advanced Welding Technology Provincial Key Laboratory,School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China)

机构地区：[1]江苏科技大学、材料科学与工程学院、先进焊接技术省级重点实验室,江苏镇江212003

出　　处：《塑性工程学报》2023年第4期61-69,共9页Journal of Plasticity Engineering

摘　　要：采用冷金属过渡焊电弧增材制造工艺成功制备了308L不锈钢单道多层薄壁件,并研究了焊接速度对结构件的成形尺寸、微观组织和力学性能的影响。结果表明,当送丝速度、层间温度等其它试验因素一定时,在试验范围内增大焊接速度,成形件的平均层高和层宽均减小,成形有效率先升高后降低。结构件各部位在室温状态下的微观组织均为奥氏体+少量残余铁素体,随着沉积层的热量累积,熔池冷却速度变慢,奥氏体晶粒尺寸逐渐变大,铁素体含量降低。焊接速度越大,晶粒尺寸更加细小,结构件的显微硬度越大,在焊接速度6 mm·s^(-1)时,可达226 HV。另外,焊接速度越大,薄壁件抗拉强度越高,断后伸长率降低,且力学性能表现出各向异性,横向抗拉强度最高可达730.37 MPa,纵向抗拉强度为686.01 MPa。通过断口分析可知,拉伸试样的断裂方式为韧性断裂。The 308L stainless steel single-pass multi-layer thin-walled parts were successfully fabricated by cold metal transfer welding(CMT)arc additive manufacturing process.The effects of welding speed on the forming dimension,microstructure and mechanical properties of structural parts were studied.The results show that when the wire feeding speed,interlayer temperature and other test factors are constant,the average layer height and layer width of formed parts decrease with the increase of welding speed within the test range,and the forming efficiency increases first and then decreases.The microstructure of each part of structural parts at room temperature is austenite+a small amount of residual ferrite.With the accumulation of heat in deposition layer,the cooling rate of molten pool slows down,the austenite grain size gradually increases and the content of ferrite decreases.The larger the welding speed is,the finer the grain size is,and the higher the microhardness value is,up to 226 HV at the welding speed of 6 mm·s^(-1).In addition,the higher the welding speed is,the higher the tensile strength of the thin-walled parts is,the lower the elongation after fracture is,and the mechanical properties present anisotropic.The maximum transverse tensile strength is 730.37 MPa and the longitudinal tensile strength is 686.01 MPa.According to fracture analysis,the fracture mode of tensile sample is ductile fracture.

关 键 词：308L不锈钢 CMT电弧增材制造 显微组织 力学性能 焊接速度 

分 类 号：TG455[金属学及工艺—焊接]