Influence of the alloying elements on phase transitions of high strength steels

Continuous Cooling Transformation (CCT) diagrams determined with a dilatometer were used to analyse the influence of the alloying elements on the phase transitions of high strength steel sheet alloys. Mo and Cr additions showed a significant influence on the extension of the bainitic region, whereas C and B additions showed noteworthy improvement in the quenchability of these steel alloys. These alloy properties are desirable requirements to be integrated in hot formed components. In addition to these experimental results, thermodynamic calculations were done with help of the JMatPro software in order to analyse the effect of Mn and C on the resulting mechanical properties as a function of the quenching rate.