| Stainless steel-carbon steel laminates is a new resource-saving and environmentfriendly composite material,which has the characteristics of stainless steel and carbon steel.Stainless steel-carbon steel laminates are widely used in many fields,such as aerospace,petrochemical industry,bridge,automobile and so on.The interlayer bonding of stainless steel-carbon steel laminates can not bear shear forces,so high-efficiency,high-precision laser cutting without contact forces is of great significance for laminates.During laser cutting of the dense leaf holes of the laminate,there is deformation of the plate,slag hangs in the slit,dimensional accuracy in the leaf hole,ablation of the missing material on the surface and slag hangs in the slit.This paper takes stainless steel-carbon steel laminates as the research object,and studies the cutting rules of the laminates and the mechanical properties of the materials in the heat affected zone through the experimental and mathematical models.(1)Establish a single factor experiment of laser cutting parameters on cutting quality,systematically study the laser parameters(laser power P,cutting speed V,auxiliary gas pressure F,defocusing amount Δ)on the cutting quality evaluation indicators(slit width,cutting The influence rule of section roughness and slag length).By designing a four-factor three-level orthogonal experiment plan,using the cutting section roughness and slag length as the optimization indicators,determining the optimal combination of laser-cut laminates.The cross-sectional quality of the slit surface is better.(2)In order to improve the dimensional accuracy of laminated board laser cutting and quickly find the compensation for dimensional interpolation,based on a single plate prediction model,combining the melting and vaporization principles and the energy conservation equation,using gas-melt ratio method laser cutting theory,establishing a mathematical model for predicting the slit width.In the single-factor experiment,several sets of parameters with a large difference in slit width are used to verify the accuracy of the prediction model.(3)Take two typical parts dense holes and leaf-shaped holes as target parts,and use the spiral scanning path method to improve the processing quality for the ablation phenomenon when processing a single round hole;For dense patterns,the dense small round hole is used as an example to propose a gasket method to solve the problem of excessive slag andunevenness in processing;For complex patterns,taking leaf-shaped holes as an example,the method of "four-stage variable speed + variable power energy compensation" is proposed to solve the problem of excessive ablation on the upper surface and slag hang on the lower surface.(4)In order to solve the performance of the plate after laser processing,Carrying out systematic research on the quality of the board.The K-type hot spot couple is used to measure the temperature near the scanning line during laser processing in order to analyze the microstructure.Using a metallurgical microscope to detect the metallographic structure near the slit to determine the width of the heat affected zone and analyze the hardness.Scanning electron microscope(FEI)was used to observe the shape of the cross-section of the cut and polished samples for obvious processing defects.Field emission scanning electron microscopy(SUPRA55)was used to perform line and surface scanning on the interface of the laminated board,line scanning to detect elements with large difference in element concentration in stainless steel and carbon steel,line scanning to detect the thickness of the transition layer of the laminate substrate and cutting sample,analyze the bonding quality of the laminate,and whether there are micro defects.using micro hardness tester to detect the hardness of the heat affected zone and analyze the changes in the structure of the plate after cutting.Using the tensile testing machine to test the sample in order to analyze the toughness and performance of the plate. |
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