Laser Welding Process And Performance Of Copper-nickel Alloy And Dissimilar Metal

Because of its excellent resistance to corrosion, BFe30-1-1 become important ocean engineering structural materials, It often relates to the welding of dissimilar materials. In this paper, laser Welding parameters for BFe30-1-1 and dissimilar materials such as Q235/304 steel are researched by IPG fiber laser and ABB six-axis welding robot. The microstructure of welded joint, tensile fracture, tensile strength and hardness are tested by optical microscope, SEM, universal tensile testing machine and micro-hardness tester.This paper selects three laser welding process parameters which are laser power, welding speed and defocusing distance, the optimized process parameters for BFe30-1-1 are obtained by orthogonal test.This paper selects 1.5KW, 1.8KW, 2.1KW as laser power levels; Welding speed levels are selected 3 values which are 25mm/s,30mm/s and 35mm/s; Defocusing distance are selected 3 values which are 1mm, 0mm and-1mm. Under the scope of the selected factor level, laser power is the ultimate affection of joint strength, next is welding speed, defocusing amount is the weak influence.Despite the different welding parameters, the micro-structure of welded joint consists of equiaxed grains and dendrite which alpha solid solutions are.Welded joint fracture mode is ductile fracture, fracture location located fusion line. Micro Hardness value of welded joint is lower than that of the base metal.he optimum joint is obtained at laser power of 2.1KW, welding speed of 30 mm/s and defocusing amount of 1mm, tensile strength of welded joint is 308 MPa.The laser beam is fixed on the copper side or on the steel side or no deviation, and copper-steel joint with nickel for BFe30-1-1 andQ235 added in is welded at laser power of 1.5KW, welding speed of 22 mm/s and defocusing distance of 1mm. When the content of Fe are far higher than that of Cu and Ni, the crack appear in welding beam. Tensile strength of welded joint is 345 MPa and welded joint fracture mode is brittle fracture. When the content of Fe are lower than that of Cu and Ni or the content of Cu, Ni, Fe are close to each other, no crack appear in welding beam. Tensile strength of welded joint is 385 MPa and welded joint fracture mode is ductile fracture. The content of Ni is higher in the welded joint with nickel added in. No cracks appear in welding beam. Fracture location is Located in the base metal of Q235, tensile strength of welded joint exceed 400 MPa. The microstructure of welded joint consists of(?Fe,Ni) and Cu-Ni solid solutions. Micro Hardness value of welded joint is higher than that of the base metal.This paper selects three laser welding process parameters which are laser power,power,welding speed and defocusing distance, the optimized process parameters for BFe30-1-1 and 304 steel are obtained by orthogonal test.This paper selects 1.4KW, 1.5KW, 1.6KW as laser power levels; Welding speed levels are selected 3 values which are 20mm/s, 22mm/s and 24mm/s; Defocusing distance are selected 3 values which are-2mm,-1mm and 0mm. Under the scope of the selected factor level,the impact of laser power, welding speed and defocusing amount are very small. The weld microstructure is mainly consisted of austenitic and single-phase solid solution of Cu-Ni. Micro hardness value of welded joint is higher than that of the base metal of BFe30-1-1, but it is lower than that of the base metal of 304 steel. Much crack appear in welded joint at laser power of 1.5 KW, welding speed of 22 mm/s and defocusing amount of 0mm. Tensile strength of welded joint is 375 MPa. The content of Fe are higher, a large number of weld cracks appear in welding beam, welded joint fracture mode is brittle fracture. Other welded joint fracture mode is ductile fracture, Fracture location is Located copper fusion line.