High strength–ductility and engineering realisation of a novel quenching–partitioning–tempering steel

Abstract

By applying appropriate quenching–partitioning–tempering (Q–P–T) processes, proposed by T. Y. Hsu (Xu Zuyao), new types of low carbon high strength steels with adequate plasticity and toughness can be obtained () In this work, the effects of tempering parameters on the microstructures and mechanical properties of Q–P–T steels were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and characterised using a Gleeble thermo-mechanical simulator and Zwick/Sans universal testing machine. The work hardening behaviour during plastic deformation was also analysed. Additionally, the characteristics of microstructures and the retained austenite stability of Q–P–T steels under different tensile temperatures were determined. Lastly, the possibility of the application of the Q–P–T processes in engineering practice was explored, and two optimised Q–P–T processes, for 12 and 20 mm thick hot rolled plates respectively, were designed.

Keywords:

• Quenching–partitioning–tempering (Q–P–T) process
• Martensite
• Retained austenite
• Mechanical properties
• Engineering application
• Hot rolled plate