On December 1, the No. 2 continuous casting machine at Henan Iron & Steel Group's Zhoukou base achieved a significant breakthrough in ultra-thick slab production, successfully producing a 460-millimeter-thick slab for the first time. This accomplishment marks a qualitative leap in the base's ultra-thick slab production capabilities, elevating its end-to-end process control to industry-leading standards. It further strengthens Henan Iron & Steel's market competitiveness in the heavy equipment manufacturing steel sector.

Compared to conventional-thickness slabs, producing 460-millimeter ultra-thick slabs involves far more than simply increasing dimensions. The core challenge lies in precisely controlling the internal quality of the steel, particularly the core properties. Conventional slabs cool relatively uniformly during solidification, allowing quality control to focus primarily on surface properties. However, the significantly larger cross-sectional dimensions of the 460mm ultra-thick slab result in slower core cooling rates. This creates susceptibility to internal defects such as central porosity and chemical segregation, leading to non-uniform properties across the slab cross-section and posing challenges to the material's overall mechanical performance.

Technical personnel from the steelmaking division at the base noted: “The key indicators for producing extra-thick slabs have shifted from single-point strength to consistent performance across the entire cross-section. We must ensure uniform and superior mechanical properties from the surface to the core—a comprehensive test of our process control capabilities.”

To achieve this, the Zhoukou base implemented systematic optimization and refined control across all stages of smelting, refining, and continuous casting. During smelting, deep molten iron pretreatment effectively reduces harmful element content in the steel. In the refining stage, precise composition adjustments, optimized argon stirring, and vacuum treatment further enhance molten steel purity. During continuous casting, technologies like intelligent water distribution via secondary cooling models and stable pulling speeds enable effective control over the solidification process, ultimately ensuring the successful production of 460mm extra-thick slabs.