Research On Temperature Field Numerical Simulation And Performance Of Laser Re-melted Ni-coating Oriented By Jet Electroforming On 45 Steel

Jet electroplating is one of high speed electrodeposition processes and can be applied to part electroplate because of its good selectivity quality. As a new kind of technology on material process and surface modification, laser re-melting can be made into high performance surface on low cost steel products, instead of high-class alloy. According to the two process features, jet electroplated coating was laser re-melted. And re-melted coating which was symmetrical, compact and joined together with substrate was obtained through re-melted technological parameters optimized, improving the wearing, corrosion resistant and mechanical performances of material.Firstly, numerical simulation method was used in studying the regular of transient temperature field of 3D moving jet electroplated coating laser re-melting in the paper. Then the laser parameters were optimized, and finally laser re-melting sample performance was tested. Works had been done as following:(1) Distribution regularity of temperature field was studied according to the heat transfer theory and numerical simulation method. Considering the thermo-physical parameters, heat convection and phase-change latent heat, computing model of transient temperature field of 3D moving jet electroplated coating laser re-melting was build up with Finite Element Method. The model was corrected after repetitive comparing and analyzing the calculated conclusion and experimental results, and then a temperature field model which could guide the experiment was established.(2) Shapes of hard zone and fused bath, temperature field distribution regularity in laser re-melting process of jet electroplated nickel coating and influences of laser power, scanning speed and facular radius to the field distribution were discussed in the paper. In order to get the hard zone which is thick and has good-quality superficial coat, laser processing parameters, such as laser power, scanning speed and facular radius, were optimized with the model established, obtaining the ideal hard zone.(3) Hardness degree, tensile strength, corrosion resistance of the laser re-melted sample were tested. And structure pattern of the jet electroformed coat on laser re-melting area, the influence of laser processing parameter to the material performance were also studied.