Thermal Characteristic Analysis And Process Optimization Of Guide Sleeve Remanufacturing

Column is an important part of mine hydraulic support,which bears a key role in rock support and underground safety protection.The guide sleeve is an important part of the column which plays the role of sealing,guiding and auxiliary support.The scratch,corrosion,wear and other failure phenomena of the pillar surface are closely related to the seal failure and wall damage of the guide sleeve.Laser additive remanufacturing technology provides the possibility of efficient,green,safe and sustainable development for the remanufacturing and repairing of the guide sleeve of hydraulic support.In this paper,aiming at the corrosion,wear and other failure phenomena of the guide sleeve of hydraulic support,the experimental research and finite element analysis of laser additive remanufacturing and repairing of the guide sleeve are carried out.The laser additive remanufacturing process of the guide sleeve of hydraulic support is divided into several local single cladding channels.The central composite test scheme is designed.40CrMo steel is used as the matrix material and Cu-8Sn-3Zn is used as the cladding layer material.The effects of laser power,scanning speed and powder feeding rate on the porosity of the single cladding channel cladding layer are studied,and the optimal process parameters are determined.The results show that the scanning speed and powder feeding rate have great influence on the cross-sectional area,total area and porosity of the cladding layer,but the scanning speed has the greatest influence,while the laser power has the least influence on the geometric characteristics and porosity;Taking the minimum porosity as the optimization objective,the optimal combination of process parameters is laser power P=1250 W,scanning speed v_s=9.43 mm·s^-1,powder feeding rate v _F=0.2 g·s^-1.Design Taguchi method test scheme,carry out the process optimization test research of single-layer multi-channel laser additive remanufacturing repair processing on the round bar,observe the macro morphology of the specimen,use metallographic microscope to measure and calculate the surface flatness,and analyze the influence of rotary speed of rotary table,axial moving speed of laser and lap ratio on the surface flatness of single-layer multi-channel cladding layer.The results show that when the laser power P=1250W,the powder feeding rate v _F=0.2g·s^-1,the laser axial moving speed v _L=0.079 mm·s^-1,the rotary speed of the turntable?=0.25mm·s-¹,the lap ratio?=50%,the surface flatness of the cladding layer is the highest.The temperature field and stress field of guide sleeve remanufacturing and repairing of40CrMo steel mining hydraulic support were numerically simulated by using finite element analysis software Simulact.Welding.The thermal cycle and stress evolution characteristics of different repairing nodes of guide sleeve were studied.The influence of different laser power,scanning speed and lap ratio on the temperature field and stress field were discussed.Based on the numerical simulation analysis of laser additive remanufacturing of guide sleeve,the experimental research on laser additive remanufacturing of guide sleeve was carried out.The influence of different laser energy density on forming quality was analyzed.The microstructure of cladding layer,heat affected zone and substrate under different laser energy density was observed,and the microhardness was measured The higher the density,the lower the cooling rate,the lower the nucleation rate,the coarser the microstructure and the lower the microhardness;the lower the laser energy density,the higher the cooling rate,the higher the nucleation rate,the finer the microstructure and the higher the microhardness.The paper has 53 figures,16 tables and 62 references.