摘要
试验采用等离子弧焊设备对工业纯镍N6板材进行填充焊丝等离子焊接工艺试验。借助光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)、X射线衍射仪(XRD)和显微硬度计等手段分析了焊接接头的微观组织和力学性能。结果表明:采用合理的焊接工艺参数可以得到成形良好的焊缝,填丝焊接接头抗拉强度为333 MPa,其抗拉强度达到母材强度的97.6%,不填丝焊接接头抗拉强度为240 MPa,达到母材强度的70.5%;母材为均匀细小的等轴晶,填丝接头焊缝处呈树枝状结晶且晶粒粗大,热影响区靠近熔池部分的晶粒过热长大,靠近母材部分为均匀细小的等轴晶;填丝接头基体为γ-Ni组织,同时存在γ'(Ni3(Al,Ti)C)强化相,填丝接头拉伸断口表现为韧-脆混合断裂,焊接接头硬度最低值出现在热影响区;与母材相比,不填丝接头焊缝区与热影响区晶粒粗大,其基体组织为单相奥氏体,不填丝接头拉伸断口表现为脆性断裂,硬度最低值出现在接头热影响区。
The industrial pure nickel N6 was experimentally studied by plasma arc welding with filler wire process. The microstruc- ture and mechanical properties of the welded joint were analyzed by optical microscope （OM）, scanning electron microscope （SEM）, energy dispersive spectrometry （ EDS）, X-ray diffraction （XRD） and microhardness test. The results showed that the joint formed well and the tensile strength of joints with filler wire was 333 MPa, which could achieve 97.6% of the base metal strength with appropriate plasma parameters, and the tensile strength of joints without filler wire was 240 MPa, which could achieve 70.5% of the base metal strength. The microstructure of base metal was fine equiaxed grains, while the weld zone of the joints welded with filler wire had gross dendrites structure. In the heat-affected area, the grains near the welding pool grew up because of overheating, while the grains near the base metal kept fine equiaxed grains. The matrix structure of welded joint with filler wire was austenite （y-Ni） with some strengthe- ning dispersion phases y1（ Ni3 （A1,Ti）C）. The tensile fracture of welded joint with filler wire was a mixed ductile-brittle fracture and the heat-affected area had the minimum hardness. The microstructure in weld zone and heat-affected area of welding joints without filler wire was coarser than that in base metal, and the matrix structure was single phase austenite. The tensile fracture of welded joint with- out filler wire was fragile fracture and the heat-affected area had the minimum hardness.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第2期103-110,共8页
Chinese Journal of Rare Metals
基金
甘肃省科技支撑计划项目(1104GKCA051)资助
关键词
工业纯镍N6
填丝等离子焊接
显微组织
力学性能
industrial pure nickel N6
plasma arc welding with filler wire
microstructure
mechanical properties
