Recently, medium-Mn steels have attracted attention for high-strength automotive components. However, because they exhibit martensitic microstructure at room temperature, low cold roll-ability is concerned so that annealing or tempering is often performed before cold rolling. Therefore, we investigated whether cold roll-ability can be improved by adjusting coiling condition in the hot rolling process. For comparison, some specimens were water-quenched or air-cooled after hot rolling. While the water-quenched specimen revealed cracks at ∼30% cold reduction, air-cooled and coiling-simulated specimens at high reductions above ∼68%. This is because the latter had lower and wider ranged hardness values compared to the former due to partial auto-tempering occurring after coiling. The higher coiling temperature caused higher cold roll-ability probably due to the active recovery of austenite. This paper is part of a Thematic Issue on Medium Manganese Steels.
Bibliographical noteFunding Information:
J.-H.N is grateful for financial support from National Research Foundation of Korea (NRF) grant funded by the Korean Government (NRF-2016-Global Ph.D. Fellowship Program).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering