Process and Solidification Microstructure of Investment Casting Steel Locomotive Couplers
In order to prevent cracks from forming in investment casting couplers and obtain dense microstructure and desirable performance,the optimum parameters for simulation orthogonal test of investment casting were determined as follows:pouring temperature of 1 570℃,preheating temperature of 425℃and pouring time of 29 s.The influence of casting temperature field and stress field on formation of shrinkage porosity and crack under optimal parameters was analyzed through casting simulation.Meanwhile,key parts of castings were simulated by KGT model.Absence of internal cracks and pores is observed by X-ray detection,and the microstructure of corresponding parts is basically con-sistent with simulated ones.The average tensile strength of coupler after heat treatment can reach 1 020 MPa.The results indicate that the casting parameters are reasonable after orthogonal optimization,and the grain is fine,of which the performance exceeds the railway standard requirements.