Effect of Cooling Rate on Secondary Dendrite Arm Spacing and Crack Defects of 42CrMo Casting

Abstract

Based on the proposed a new technology casting-rolling continuously forming of ring parts,it is considered to detail organization,improve the quality of castings,and avoid the crack defects.Numerical simulations of temperature field and stress field are taken respectively in 42 CrMo of sand mold and metal mold casting,solidification cooling process and the crack tendency prediction is studied by using the simulation results.The greater cooling rate in the cast was,the longer the casting stayed in the mold and the bigger the casting shrinkage is,the greater thermal stress will became,the greater the inclination of forming crack isare.The part of the edge is the easier to form cracking.By the numerical simulation of the microstructure for the casting,the functions of the cooling velocity and the secondary dendrite arm spacing are established.The effect of cooling rate on the organization performance is analyzed.It is obtained that the casting performance is the better using the metal mold casting than using the sand mold casting.Comparing the two casting methods,it is identified that the higher quality and no defects casting may be got when casting temperature out of the mold about 1 050 ℃.It can be satisfied in technology requirement based on casting-rolling continuously forming of ring parts.Analysis results may provide a theoretical reference for forecast the quality of castings and experiments.