Interphase precipitation hardening of a TiMo microalloyed dual-phase steel produced by continuous cooling

Precipitation hardening is a promising way to strengthen the ferrite phase in dual-phase steels. This work studied the microstructure and precipitation behaviour of a TiMo microalloyed steel processed by continuous cooling. A dual-phase steel with interphase precipitation-strengthened ferrite has been successfully produced by continuous cooling. Transmission electron microscopy and atom probe tomography proved that precipitates formed during continuous cooling were nano-sized (Ti, Mo)C interphase precipitates. More importantly, the interphase precipitation-strengthened ferrite phase became harder than the bainite phase, leading to a new strategy for producing dual-phase steels. The continuous cooling process for interphase precipitation can be used for a wide range of conventional steel production lines, since there is no need for coiling operation of hot strip mills.

Automated summary

This study successfully used continuous cooling process to achieve interphase precipitation-strengthened ferrite in dual-phase steels, with nano-sized (Ti, Mo) C interphase precipitates forming hardened ferrite phase, providing a new strategy for dual-phase steel production.