Effect of V on the Hot Ductility Behavior of High-Strength Hot-Stamped Steels and Associated Microstructural Features

The application of microalloying technology has been emerging as an effective method to enhance the strength-ductility synergy of high-strength hot-stamped steels, although the impact of microalloying elements on the hot ductility of hot-stamped steels remains an open question. In this work, we systematically studied the hot ductility behavior of V microalloyed hot-stamped steels, covering a broad temperature range from 650 & DEG;C to 1300 & DEG;C. It is found that a hot brittle range exists at testing temperatures ranging from 650 & DEG;C to 900 & DEG;C, with the hot ductility gradually decreasing between 900 & DEG;C and 650 & DEG;C. An increase in microalloying elements is not beneficial to hot ductility in this temperature range. Detailed microstructural analysis and thermodynamic calculation show that the deterioration of hot ductility from 900 & DEG;C to 650 & DEG;C is closely related to the formation of proeutectoid ferrite and nano-scaled precipitation.

Automated summary

The application of microalloying technology is an effective method to enhance the strength-ductility synergy of high-strength hot-stamped steels. However, the impact of microalloying elements on the hot ductility of hot-stamped steels is still unknown. In this study, the hot ductility behavior of V microalloyed hot-stamped steels was systematically investigated over a wide temperature range from 650°C to 1300°C. It was observed that a hot brittle range exists between 650°C and 900°C, with hot ductility gradually decreasing between 900°C and 650°C. Increasing microalloying elements does not improve hot ductility within this temperature range. Detailed microstructural analysis and thermodynamic calculation revealed that the deterioration of hot ductility from 900°C to 650°C is closely related to the formation of proeutectoid ferrite and nano-scaled precipitation.