Recently, Qinhuangdao Baigong Iron and Steel Co., Ltd. successfully completed a 100T industrial trial production of low-density medium-Mn steel, covering the entire integrated process of “converter–continuous casting–continuous rolling.” This achievement marks the world’s first mass-production-level enabling stable and smooth operation of the full continuous casting and rolling process for low-density medium-Mn steel, signifying that the material has officially progressed from the laboratory research stage to industrial-scale production.
This achievement was accomplished by a project team led by Professor Dong Han of Shanghai University. As a core member, Professor Cai Minghui played an important role in tackling key process challenges in the industrial trial production of low-density medium-Mn steel by leveraging his profound expertise in metal material processing. The team successfully overcame multiple technical bottlenecks in the continuous casting and rolling process of this steel grade. The molten steel casting conditions remained stable and controllable, enabling continuous casting from a 100T ladle; the casting billet exhibited good quality without defects; the hot-rolled strip steel showed excellent surface quality and met dimensional tolerance requirements. The entire production line, from smelting to finished product formation, operated smoothly, achieving for the first time stable industrial operation across the full process.
Low-density medium-Mn steel is a new class of advanced iron and steel materials that combines high strength with reduced density. Its density is approximately 5–15% lower than that of conventional steels while maintaining excellent mechanical properties and formability. As such, it is a key material for automotive lightweight design and high-strength weight reduction. Due to its complex alloy composition and distinctive solidification characteristics, however, this steel grade is prone to defects such as cracking and segregation during the continuous casting process. In the continuous rolling stage, the processing window is narrow and microstructure control is highly challenging. As a result, industrial production has long been plagued by significant technical bottlenecks, and no successful case of a fully integrated process had previously been reported worldwide.
Industry analysts note that breakthroughs in the industrial-scale production technology of low-density medium-Mn steel will provide critical material support for sectors such as lightweight vehicle manufacturing and high-end equipment production, effectively addressing the growing demand for lightweight materials in the automotive lightweight design market. At the same time, this technology holds significant strategic value for advancing the transformation and upgrading of the Chinese iron and steel industry toward high-end, green, and low-carbon development, while also fostering new quality productive forces in the metallurgical sector.
