Study of one-step and two-step quench and partition heat treatments on a medium carbon high silicon alloy using dilatometry

Abstract

This study evaluated the microstructural evolution in a medium carbon high silicon steel during one-step, and two-step quench and partition (Q&P) processes using dilatometry experiments. The two-step Q&P process was carried out using different quench temperatures ranging from 180 to 260 °C. In the one-step process, Q&P heat treatment samples were held isothermally for ten minutes after quenching at specified temperatures ranging between 200 and 4°50 C. The two-step Q&P process yielded a higher fraction of retained austenite than a one-step Q&P process. During the isothermal hold step, the volume expansion due to carbon partitioning and austenite decomposition behavior was interpreted by experimentally determined strain values. For the one-step Q&P process, the austenite decomposition kinetics above and below the Ms temperature differed, as evidenced by the JMAK parameters. The TTT diagram generated for the one-step Q & P process showed a “swing back” at a temperature of around 355 °C.

Influence of Quenching and Partitioning on the Mechanical Properties of Low‐Silicon 33MnCrB5 Boron Steel

“…The presence of RA should be tailored to achieve the desired mechanical properties of the final material. [6][7][8][9] Moreover, it must be noticed that, depending on the morphology and stability of austenitic particles, and on the surrounding microstructure, different strain-induced transformation kinetics are obtained, thus introducing different properties in the material. [10][11][12] Several studies have shown that the final properties obtained through this treatment, depending on the steel grade, can reach an UTS of 1600-2000 MPa associated with good values of elongation at break: these properties are not achieved with traditional quenching and tempering (QT) treatments.…”