Influence Of Process Parameters And Scanning Strategy On Surface Properties Of Die Steel Cladding Layer

With the progress of social science and technology,China has become a manufacturing power.Manufacturing has not only brought a lot of economic wealth to human beings,but also exploited a lot of resources on the earth.With the use of products,a lot of industrial wastes will be generated.Green remanufacturing engineering is a general term for a series of technical measures or activities used to repair and transform the worn parts by combining advanced manufacturing technology with industrial production,so as to obtain products with excellent properties such as wear resistance,corrosion resistance and oxidation resistance and reduce the waste of resources.Laser cladding repair is a new technology integrating manufacturing and repair.Laser cladding technology uses high energy density laser beam as heat source,irradiates the substrate surface,and combines metal powder melting deposition with the surface metallurgy of the workpiece in different powder feeding ways to obtain the cladding layer with good performance.Laser cladding technology is mostly used in parts of the surface modification,repair,and increase material manufacturing and other fields,the workpiece surface crack repair,can restore the appearance of wearing parts dimension and physical properties,satisfy different working conditions should have properties of the metal parts,make our products to improve physical properties,can prolong its service life.At present,laser cladding technology has been widely used in many fields such as aerospace,industrial manufacturing,energy and chemical industry,and has a good application prospect.In this context,H13 die steel was selected as the matrix material,and Ni60 A self-fusible alloy powder was used to conduct numerical simulation test of laser cladding.The specific research contents are as follows:(1)Based on the existing literature and reference materials,a 3d transient numerical model of laser cladding was established to calculate the thermal physical property parameters of the matrix and cladding materials,and the thermal physical value of the material melting point and its change with temperature was obtained.(2)Three factors and three levels orthogonal test(laser power,scanning speed,spot diameter)was designed.Based on the above 9 groups of process parameters,ANSYS APDL module was used to conduct numerical simulation of laser cladding test,extract the temperature in the center of the molten pool during the cladding process,and determine whether the material melting point has been reached.The results are applied to solve the load stress field,temperature field definition along the path of the scanning direction,extraction of the cladding layer and substrate combination zone node along the change of stress path direction is in to ensure good metallurgical bonding coating and substrate,on the basis of according to the final nine group parameters of simulation test the mean stress,choosing a group with minimum stress value as the optimal process parameters.(3)based on the orthogonal experiment it is concluded that the optimal process parameters,design different scanning strategy plan,single-layer multi-channel laser cladding simulation test,the molten pool morphology under different scanning path,node time history curve analysis and research,the loading temperature field results in stress field coupling calculation analysis,node in different direction changes with the path of the residual stress value,The optimal scanning path is determined according to the minimum stress value.Combined with the merits and demerits of the single-layer multi-channel scan path design multilayer composite scanning path of laser cladding on multichannel approach,analysis of the laser after forming the different location of molten pool temperature,to explore the path to the superposition of cladding layer heat accumulation on the depth of different directions of heat affected,with the minimum residual stress as the evaluation index,determine the multilayer multi-channel laser cladding with optimal scanning path.Through the above finite element simulation results of laser cladding,the optimized process parameters were determined as follows: laser power 800 W,scanning speed 10mm/s,spot diameter 2mm;In the simulation test of single-layer multi-channel cladding,the stress value in the bonding zone between the matrix and cladding material is the minimum when the laser forming is carried out by short-path scanning.In the multi-layer and multi-channel laser cladding stacking test,the residual stress value obtained by short-path + spiral composite scanning method is the smallest,which can disperse the stress distribution and reduce the deformation in local area.The optimized process parameters and scanning strategy can provide theoretical guidance for laser cladding repair experiments.