层间温度对CMT电弧增材制造2Cr13不锈钢薄壁件成形及组织和性能影响  

Effect of interlayer temperature on the forming,microstructure and mechanical properties of 2Cr13 stainless steel thin-walled parts by CMT arc additive manufacturing

作　　者：李敬勇[1] 李超然 徐育烺 钱鹏 Li Jingyong;Li Chaoran;Xu Yulang;Qian Peng(Advanced Welding Technology Provincial Key Laboratory,Jiangsu University of Science and Technology,Zhenjiang 212003,Jiangsu,China)

机构地区：[1]江苏科技大学,先进焊接技术省级重点实验室,江苏镇江212003

出　　处：《焊接》2024年第2期43-50,共8页Welding & Joining

摘　　要：该文利用冷金属过渡(Cold metal transfer,CMT)技术,使用电弧丝材增材制造系统制造2Cr13马氏体不锈钢单道多层薄壁试样,并研究了不同层间温度(100℃,150℃和200℃)对薄壁试样表面成形,微观组织和力学性能的影响。研究结果表明,较高的层间温度会使得薄壁成形件整体温度升高,散热状况变差,熔池高温存在时间增长,熔融金属流动性增强,最终导致成形件表面变差甚至塌陷。成形件中部组织在经历反复加热和冷却过程后,主要由极为细长的板条马氏体组成,并伴有少量铁素体以及沿铁素体晶界析出的碳化物。靠近重熔区位置由于熔池的热作用会导致马氏体组织过热而发生相变,形成密集的铁素体。随着层间温度减小,成形件晶粒尺寸和分布更为细小均匀;另外,弥散分布在铁素体晶界上的碳化物阻碍位错运动,两者的共同作用使得显微硬度和抗拉强度随层间温度降低而升高,同时拉伸试样的断后伸长率也随之增大。拉伸断裂形式均为韧性断裂,随着层间温度的减小,同取样方向上拉伸试样断口尺寸越来越大,韧窝也越来越深。In this paper,single-pass multi-layer thin-walled specimens of 2Cr13 martensitic stainless steel were fabricated by arc wire additive manufacturing system with cold metal transition(Cold metal transfer,CMT)technology.The effects of different interlayer temperatures(100℃,150℃ and 200℃)on the surface forming,microstructure evolution and mechanical properties of thin-walled specimens were studied.The results showed that higher interlayer temperature would increase the overall temperature of the forming parts,worsen the heat dissipation,increase the existence time of the molten pool,enhance the fluidity of the molten metal,and ultimately result in the deterioration or even collapse of the surface of the forming parts.Due to the repeated heating and cooling process,the middle part microstructure of the forming parts were mainly composed of extremely slender lath martensite,accompanied by a small amount of ferrite and carbides precipitated along the ferrite grain boundary.Near the remelting zone,due to the thermal action of the molten pool,the martensite structure would be overheated and undergone phase transformation to form dense ferrite.With the decrease of interlayer temperature,the grain size of the forming parts was smaller and the distribution was more uniform.In addition,the dispersed carbides on the ferrite grain boundary hindered the dislocation movement.The combined action of the two mentioned above made the microhardness and tensile strength increase with the decrease of interlayer temperature,and the elongation of the tensile specimen was also enhanced at the same time.The tensile fracture forms were all ductile fracture,with the decreasing of interlayer temperature,the fracture size became larger and larger,and the dimple became deeper and deeper in the same sampling direction.

关 键 词：电弧增材制造 2Cr13马氏体不锈钢 层间温度 组织和性能 

分 类 号：TG455[金属学及工艺—焊接]