Microstructure and mechanical properties of a hot pressing-dynamic partition treated steel

ABSTRACT

The microstructure and mechanical property of improved press-hardened steel with hot pressing combined dynamic partitioning (HP-DP) treatment are presented. Microstructure of the steel subjected to HP-DP treatment is featured by multi-martensite phases and the retained austenite (RA) phase with carbon content gradient. Compared with conventional hot-pressed samples, the HP-DP samples show better tensile property especially ductility. The effect of HP-DP parameters on the evolution of RA and mechanical property is then discussed. Finally, hot pressing of a double U-shaped part using both 22MnB5 steel sheet and the developed HP-DP steel sheet was carried out with exact control of part temperature at the end of hot pressing followed by air cooling.

KEYWORDS:

• Hot pressing
• dynamic partition
• retained austenite
• tensile property
• product of strength and elongation

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The financial support of NSFC projects 51274063 and 51034009 is acknowledged.