Stainless Steel Multi-channel Laser Cladding Ni-based Coating On The Surface Stress Field Analysis And Numerical Simulation

Stainless steel is realized to a social sustainable development of green material in the 21st century. Laser cladding is now a rapid development of laser surface engineering technology, and it can make cladding powder particles interact with base material, generating metallurgy chemical reaction pool by the high energy density of laser beam. Laser cladding application and development are introduced in 1Cr18Ni9Ti stainless steel materials research background, in this paper are systematically researched from the laser cladding material system, laser cladding process optimization, cladding layer crack formation and control, multi-channel laser cladding physical model and numerical simulation of the different aspects in laser cladding.XRD results show that the coating is mainly (Fe, Ni) solid solution, W2C by WC in-situ reaction, and contains CrNiFeC, CU3.8Ni compounds and some hard-phase such of FeW3C, Ni2Si, Fe3Ni3B. SEM analysis for cladding coating display that branch of intergranular exist lots of different radial shape W2C and W2C by WC and in-situ reaction, and enrichment in (Fe, Ni) solid solution boundary with circular, flake, different of size and shape. Some hard-phase such as W2C, WC, FeW3C, Ni2Si and Fe3Ni3 cause grain boundaries enrichment.EDAX analysis found that mainly contain Si, Mn, C, Cu, Fe, Ni, W.The results of microhardness testing revealed that different cladding layer microhardness were significantly higher that substrate (substrate about 176 HV). The microhardness of double layers for the second layer is the highest, achieved 650 HV increased 3 times that substrate. The microhardness of BZ is in the range of 280～440 HV. The microhardness of HAZ is higher that substrate, achieved 324 HV.The process of single-pass lap and multi-pass lap laser cladding coatings conduct the temperature field simulation. Single-pass lap temperature field analysis results that the maximum temperature is in the center of the flare. Temperature is achieved 3786℃in the center of CZ. The more preheating temperature and laser power increases the more maximum temperature and maximum cooling rate increases, but for the cooling rate is difference from overall and single-pass lap temperature field changes similar with multi-pass lap laser cladding coatings. The first layer of multi-pass lap form middle to end still reaches 2028℃, the end of coating achieved 1622℃, the temperature of lap area reached 1217℃. It realizes to melt in the part of first layer. Heat affected zone of substrate reaches 811℃. The process of multi-pass lap laser cladding coatings conducts the stress and strain field simulation. Stress field analysis results that the maximum stress appeared in the center of lap area, the first layer and HAZ of the second layer, its alues for 488 MPa,237 MP and 833 MPa, respectively. The maximum strian appeared at the edge of coating with substrate, achieved 0.030 m, second in the center of cladding coating. The total strain of HAZ reaches 0.0032 m. The residual sress of different area results show that cladding coating is in tensile stress state, substrate is in compressive state. The maxmum tensile stress appears in lap area, its value for 1178 MPa.