Application of the Quenching and Partitioning (QP) Process to a Medium-Carbon, High-Si Microalloyed Bar Steel

摘要

Recently a new process referred to as quenching and partitioning (Q&P), was proposed to produce steels with controlled volume fractions of carbon-enriched retained austenite at room temperature. The basic features of the Q&P process are reviewed and results on a 0.35C, 1.3 Mn, 0.74 Si microalloyed bar steel are presented. Samples were austenitized, quenched into a tin-bismuth bath at various quench temperatures, and held for various times at temperatures referred to as the partitioning temperatures. Microstructures were assessed, and the amount of retained austenite at room temperature was characterized using x-ray diffraction. The volume fraction of austenite retained at room temperature was shown to depend on the quench temperature, partitioning temperature, and partitioning time. These results are compared to predictions, and implications of Q&P processing on new product development opportunities are considered.