Computer Simulation of Quenching and Tempering of Cast Steel

摘要

Since working stress of cast steel directly depends on toughness and yield strength, these two mechanical properties are investigated. The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of homogenization and normalization, on yield strength and Charpy-V notch toughness of quenched and tempered cast steel was investigated.Experimental procedure of material properties optimization was done using the 25"2 factor experiment on cast steel, EN GS-42CrMo4. It was found out that yield strength of cast steel is insensitive on differences between applied manufacturing processes, but with appropriate pouring temperature the Charpy-V notch toughness of cast steel is increasing. Also, because of absence of interactive effect of the appropriate cooling rate during the casting and application of hot working Charpy-V notch toughness of cast steel is less than of steel. By microstructure analysis, it was found out that hot worked and normalized specimens have refined microstructure. Austenitic grain size of investigated cast steel has ASTM number of previous austenite grain size equal to N.4-5, while austenitic grain size of steel treated by hot working has ASTM number of previous austenite grain size equal to N.6-7.New relations between the Charpy-V notch toughness, and hardness of quenched and tempered cast steel was established. The established algorithms can be used in computer simulation of Charpy-V notch toughness of quenched and tempered cast steel.