Study On The CMT-TWIN Technology For Cladding Nickel-based Alloy On Q235 Steel And 304 Stainless Steel Surfaces

In this paper, CMT-TWIN (cold metal transfer-twin) technology is used to clad Incone1625 nickel-base alloy layer on Q235 steel and 304 stainess steel respectively with ERNiCrMo-3(Φ1.0), to enhance the corrosion resistance and high temperature oxidation resistance of the substrate surface. By orthogonal experiment, the optimum double wire parameters obtained on Q235 base are:arc voltage is 15.8V, welding current is 113A, welding speed is 4mm/s and swing wide is 14mm; on 304 stainless steel substrate, the optimum double wire parameters are:arc voltage is 15.6V, welding current is 105A, welding speed is 5mm/s and swing wide is 8mm. Both optimum parameters can obtain a beautiful multi-passed Incone1625 surfacing layers without pores, cracks and other macro defects.Mechanical tests show the shear strength between Q235 and surfacing layer is greater than 320MPa, and the fracture occurs in the heat-affected zone of the matrix; while the shear strength between 304 stainless steel and the surfacing layer is more than 470MPa, and the fracture occurs in the fusion zone. Both samples dimple fracture show the fracture modes are ductile fracture. Microhardness tests show the hardness of Incone1625 surfacing layer on two substrates are between 240-280HV, and the distribution are more uniform.Metallographic observations show the Incone1625 alloy layer on the two different substrates are combined well and without pores, cracks, none fusion defects; from the interface to the surface, the structures of the surfacing layers are columnar and dendrite morphology growth of austenite.XRD tests show the surfacing layers are y-phase; EDS tests show Ni, Cr, Nb, Mo, and other major elements are distributed more homogeneous in the surfacing layer, which meets the required compositions of Incone1625 nickel base alloy; but the composition mutation occurs in the binding region and the mutations zone is very narrow (about 10-20μm), which indicates the dilution rate between the matrix and the cladding layer is lower, the fusion ratio is small and the penetration depth is shallow.