Recently, Jiuquan Iron & Steel Group (JISCO) added another core member to its product portfolio: Hongxing Steel's rolling mill successfully rolled a 100×2200×8000mm Q355B extra-thick wide plate, reaching the production line's maximum designed thickness.
Due to its characteristics of small compression ratio, large cross-sectional size, and high thickness precision control, extra-thick wide plates have put forward stringent requirements on heating regime, rolling rhythm, and the accuracy of the rolling die, and have long been a "hard nut to crack" in the development of thick-gauge products in the steel industry. The successful rolling of this 100mm-thick wide plate is the result of in-depth collaborative efforts across multiple departments, including production, process, and equipment. The steel mill set up a special task force and established a "closed-loop management and control" mechanism for the entire process, systematically optimizing and upgrading each key link from billet entering the furnace to finished product leaving the warehouse.
In the heating process, addressing the pain points of uneven heating and temperature differences in the core of the 320mm thick large-section steel billet, the team innovatively designed a "zoned temperature control" system. By adjusting the temperature gradient of each area of the heating furnace and extending the heating time, combined with real-time temperature monitoring feedback, the temperature difference between the core and surface of the steel billet can be precisely controlled within ±15℃. This completely solves the problem of insufficient rolling stability caused by traditional heating methods and lays a solid foundation for subsequent rolling processes.
Technological breakthroughs in the rolling process are particularly crucial. The process technology team relies on SMS's intelligent algorithm model to precisely design core parameters such as rolling passes, reduction distribution, and deformation rate, and innovatively form a "gradient reduction + balanced deformation" rolling scheme. This method involves crushing the internal structure of the steel billet with heavy pressure in the first pass and precisely controlling the shape in the subsequent passes to ensure dimensional accuracy. Ultimately, the thickness deviation of the finished steel plate is stably controlled within ±0.3mm, and the surface quality and internal grain uniformity both meet the process standards.
To address common industry challenges such as difficulty in controlling thickness accuracy and the susceptibility to cracking during the rolling of extra-thick plates, the equipment team simultaneously upgraded the temperature monitoring device and the rolling rhythm control system. By adding infrared temperature measurement points at the mill inlet and dynamically adjusting the rolling interval, they ensured that the steel plate remained within the optimal rollable temperature range throughout the rolling process, thus guaranteeing the stability of the rolling process.
According to reports, this technological breakthrough not only verified the equipment limits and technology integration level of the rolling mill's heavy plate production line, but also solidified a set of core process parameters and management experience for the production of extra-thick plates, providing technical support for the company to expand its customized production business. Currently, the steel mill has launched a project to tackle the challenges of products with extreme specifications. Going forward, it will focus on making breakthroughs in the stable production technology of 12mm thin plates and ultra-wide steel plates, and continuously improve the product matrix of wide and thick plates, so as to help the company seize the initiative in the wave of transformation and upgrading in the steel industry.