Research on a New Process of the Non-quenched and Tempered Steel with High Strength and High Toughness

The controlled-forging and controlled-cooling has become the main process of the non-quenched and tempered steels now. However, there is a problem that the unstable toughness and its lower values restrict the expanded application and the development of the steels. In this study, the process of the non-quenched and tempered steels was optimized through the micro- alloying and the controlled-forging and controlled-cooling technology. The simulated rapid cooling followed by self tempering after forging was tried to control the microstructure and mechanical properties of the steels. A new process of the non-quenched and tempered steels was proposed to ensure high strength and high toughness for the studied steels. The toughening and strengthening mechanism of the steels processed by the new process was discussed and evaluated, which could provide the fundamental theory, technical support and process parameters for the industrialized production of the high strength and high toughness non-quenched and tempered steels.