Effect of Subsequent Continued Heating After Hot Rolling on the Microstructures and Mechanical Properties of Hot-Rolled Super Ferritic Stainless Steels

In addressing the significant tendency towards embrittlement in the hot-rolled super ferritic stainless steels (SFSSs), which is prone to cracking and tape breakage during the coiling and uncoiling process, this study introduces a "subsequent continued heating" method to mitigate the post-rolling work-hardened microstructure, and inhibit the precipitation of brittle phases during the cooling process, consequently eliminating the risk of embrittlement and cracking in hot-rolled SFSS plates. The heating process, which is conducted immediately as the samples roll out from the rollers, is called subsequent continued heating. The effects of continued heating treatment on microstructure evolution, precipitation behavior, and mechanical properties of hot-rolled SFSS were studied. The results show that the continued heating treatment after hot rolling can eliminate the deformation structure, reduce the dislocation density, and eliminate the work-hardening effect. Furthermore, it can dissolve both the sigma phase and Laves phase generated during the hot rolling process and slow down the precipitation tendency of the sigma phase and Laves phase formed during the hot rolling cooling process, retard the precipitation trend of the sigma phase during the cooling process, thereby providing a sufficient time window for the cooling after the hot rolling. Continued heating treatment can reduce the strength of the hot-rolled plates, improve their plasticity and impact toughness, and ensure sufficient plasticity for subsequent coiling/uncoiling operations, thereby increasing the yield of SFSSs production.