Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel

Abstract

Achieving strength-ductility synergy of hot-stamping steel via microalloying technology has attracted great attention due to their pronounced precipitation strengthening. Nevertheless, the precipitation behaviours and characteristics have not been clearly unveiled. In this work, the effects of V content on the microstructure and mechanical properties of 1800 MPa grade hot-stamping steel are systematically studied. Massive V contained precipitates develop after hot-rolling and coiling, which refine the martensitic microstructure and retain in the matrix after austenitizing and quenching. The refined martensite with massive precipitates is responsible for the good mechanical properties. Generally, the tensile strength decreases slightly with increasing V content from 0.04% to 0.2%, as V consumes C in the martensite matrix by forming carbides and promoting precipitate coarsening.

KEYWORDS:

• Hot-stamping steel
• microalloying elements
• precipitation
• mechanical properties
• strengthening mechanisms

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was financially supported by the National State Key Research and Development Program (No. 2021YFB3702403), National Natural Science Foundation of China (No. 52071038, 52122408, and 52071023).