High strength vanadium micro-alloyed steels for forgings: influence of quenching and tempering temperatures

The production of heavy steel forgings of micro-alloyed steels gives the possibility to obtain advantages associated with the benefit of the application of micro-alloying elements and thermo-mechanical treatments for improving the mechanical properties of forgings up to level by sheets, strips and tubes. In order to do that, the effect of V addition has been exploited by means of metallurgical modelling followed by a laboratory ingot manufacturing. Heat treatment has been designed aimed to achieve the desired target tensile properties. Results show that ASTM A694 F70 grade requirements can be fulfilled by 0.15 % V addition and a proper heat treatment in a ferrite-pearlite microstructure, representative of a forged component. In this paper the influence of quenching and tempering (Q&T) temperatures on the mechanical properties and microstructure of F70 steel according to ASTM A694 is reported.