Numerical Assessment Of The Effect Of Quenching Conditions On The Case Hardening Depth Of Astaloy CrA Sintered Steel

Case hardening in conjunction with low pressure carburization is a promising technology to enhance the load bearing capacity of structural components produced by powder compaction and sintering. By both lowering the effective stress by introducing compressive residual stresses and increasing the strength by the formation of martensite, case hardening offers a unique potential. However, the complexity of the process on a component scale aggravates the utilisation of its full potential. Hence, a numerical model for Astaloy CrA with 1% Ni is derived that allows for the computation of the local microstructural composition, the hardness and the residual stresses while accounting for the local carbon concentration. The model is based on extensive dilatometric and microstructural investigations that are conducted to describe the material behaviour during heat treatment. The model is validated by comparing simulated hardness profiles with experimental results obtained on sintered gears that were subjected to various quenching conditions.