Strong and ductile medium manganese steel processed by low-temperature partitioning

Abstract

Conventional medium Mn steels processed by intercritical annealing (IA) demonstrate low yield strength. The present work investigates the effect of low-temperature partitioning (LTP) on the microstructure and tensile properties of medium Mn steel. It is found that medium Mn steel processed by LTP at 300°C possesses ultra-high yield strength of 1683 MPa and proper uniform elongation of 11.3%. The LTP process does not reduce the yield strength but substantially enhances the tensile ductility. The increase of the tensile ductility after LTP treatment can be ascribed to the reduction of the residual stress, martensitic transformation, and the well-developed ductile fracture behaviour. The present LTP process provides an alternative pathway to develop strong and ductile medium Mn steel.

KEYWORDS:

• Low-temperature partitioning
• intercritical annealing
• medium Mn steel

Acknowledgement

The authors would like to acknowledge the technical support from SUS Tech Core Research Facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Science and Technology Innovation Commission of Shenzhen [grant number JCYJ20210324120209026; KQTD2019092917250571]; National Natural Science Foundation of China [grant number U52071173].