Composition design and experimental verification of economically air-quenching steel for heavy section casting

In order to resolve the problem of deformation and cracking of castings during quenching, the design of chemical compositions and the determination of quenching size effects for CrMnSiMoTi system economically air-quenching cast steel have been undertaken based on the calculations using Bhadeshia austenite decomposition model and non-linear FEM thermo-analysis, and the experimentally verification has also been carried out. The results show that the allowable maximum diameter in which there is no non-hardened microstructure occurring at the core of 0.45-0.70C-2.50Cr-1.65Mn-1.25Si-0.20Mo-0.15Ti system cast steel bar during air quenching is about in the range of 080 mm to 0140 mm and the microstructures at surface and core of the steel bar are all complex bainite/martensite. The basically agreement between the predictions obtained from the computer calculations and the experiment indicates that the designed steel can be used as the candidate materials for economically air-quenching cast steel.