Reseach Of Laser Cladding Fe Based Thick-wear-resistant Coating And Forming Quality Control

Laser cladding is a technique that using high energy density laser to change the surface properties of material into high performance,The Fe based alloy powder has more practical significance in cladding researchs because of its low price,high hardness and excellent wear resistance.With the Requirement of Mechanical property improving,the direction of processing material by laser cladding is developing toward the large area,high thickness,high hardness and good wear-resisting.It is more easier to appear crack or unstable forming quality problems in the process of preparing thick-wear-resist cladding layer.Under the above background,this paper has designed the cladding alloy powder,Prepared the thick-wear-resistant cladding layer with hardness changing by discontinuous multi-layer cladding technology.The main work of this paper is around the following aspects:Based on the characteristics during solidification and defect generation process of laser cladding.Analysis the factor that cause cracks in laser cladding coat and verify the process by continuous and discontinuous processing.According to thr design principles of cladding materials,designed three Fe based alloy powder,Using suitable process prepared the thick-wear-resistant cladding layer with smooth and crack free Surface.The regional microstructure analysis and the micro hardness test has done on thick-wear-resistant coating,Contrasting the coating’s mechanical property with 45 steel and single layer wear resistant coating by testing tensile and impact properties of the coating,The wear resistance of the coating is detected by the friction and wear testing machine.The laser cladding layer’s morphology size determine its Forming quality and precision,the process parameters have direct influence on the macro size of coating.Exploring the the relationship between different process parameters and cladding layer size and binding property based on the large number of previous experiment,Got change law among cladding width,height,weld pool depth and laser power,scanning speed,paving powder thickness.Lay the foundation to achieve the goal that control the layer forming quality.Established the non-linear model between laser processing parameters and cladding layer’s morphology quality,Though the experimental analysis and theoretical research with laser power,scanning speed,paving powder thickness as the main cladding layer influencing factors by Genetic algorithm optimization BP neural network.and the absolute errors of prediction about cladding width,height,weld pool depth are small,Can be applied to cladding process parameter optimization and control the layer forming quality...