Quenching and partitioning in hot stamped steels

Hot stamping is a technique suitable for making high strength components with limited ductility related to a martensitic microstructure. The present work shows the quenching and partitioning heat treatment integrated into the traditional hot stamping process, for 22MnB5 alloy and high Si steel. The above, in order to produce a   microstructure containing retained austenite and martensite to improve the ductility of resultant components. The investigations of quenching and partitioning process were made by means of dilatometry and hot stamping - quenching and partitioning (HS-Q&P) process experiments by a special experimental tool. To investigate this microstructure, specimens were heated to the austenitization temperature of 920 °C, held for 3 minutes. Then quenched until reach corresponding percent martensitic temperatures, which is between the Ms and Mf temperatures. Finally cooled to room temperature to stabilize the carbon-enriched retained austenite.  The resulting microstructure was examined using light optical and scanning electron microscopy as X-ray diffraction too. Some results obtained shown that compared with conventional hot stamping samples, the HS-Q&P process improves elongation effectively and maintains high-strength at the same time.