Microstructure and Mechanical Properties of a Low Alloy High Carbon Steel Processed by Quenching and Partitioning Process

The quenching and partitioning (Q&P) process is a new heat treatment cycle to produce the third generation of advanced high strength steels based on diffusion of carbon from martensite to retained austenite phase. The application of this process for various steels leads to a remarkable combination of mechanical properties including high strength and good ductility. Using this process in automotive industry causes better mechanical performance, greater car safety, weight saving and cost reduction. In this study, a low alloy high carbon steel has been subjected to Q&P process and its microstructure and mechanical properties have been investigated. The results showed that the microstructure of the quenched and partitioned steel contains carbon-enriched stabilized austenite and carbon-depleted martensite resulting in increasing the strength of steel with an acceptable ductility. Conducting Q&P heat treatment caused the retained austenite content and the hardness of steel to increase. Fracture in specimens treated by Q&P process was of brittle type and their fracture surface was considered to be quasi-cleavage.