1、 Core role: a hub for efficient production and quality control

The hot rolling group is the core link in achieving continuity, automation, and efficiency in steel rolling production, and its role runs through the entire process from raw materials to finished products:

1. Continuous production to improve efficiency

Through the series design of rough rolling and precision rolling, the hot rolling group directly rolls the heated slab into the required specifications of strip steel, eliminating the intermediate cooling and reheating steps. For example, the 2300 production line of Benxi Iron and Steel has increased its hourly output from 360 tons to 420 tons by optimizing the rolling rhythm, resulting in a significant improvement in efficiency.

2. Precise control to ensure quality

Thickness accuracy: Using hydraulic AGC (automatic thickness control) technology, combined with high-precision mathematical models, the thickness deviation of the strip steel is controlled within ± 0.01mm.

● Plate shape control: By using the strong bending roll system (WRB), work roll running (HCW/CVC), and cross roll (PC) technology, plate shape defects such as edge waves and center waves are eliminated. For example, the application of CVCPLUS technology in Shougang's relocated 2160mm production line has increased the plate shape qualification rate to over 98%.

Temperature uniformity: The laminar cooling device precisely controls the final rolling temperature to ensure uniform metallographic structure and stable mechanical properties of the strip steel.

3. Flexible production to meet diverse needs

Modern hot rolling mills can flexibly adjust rolling specifications to achieve full coverage of strip steel from ultra-thin (0.8mm) to ultra thick (28mm). For example, the ESP production line of Rizhao Iron and Steel uses headless rolling technology to mass produce 0.8-1.2mm ultra-thin strip steel, filling the domestic gap.

2、 Technological development: a leap from scale to intelligence

Hot rolling technology has undergone a century of evolution and currently presents the following development trends:

1. Process technology reduces energy consumption

Thin slab continuous casting and rolling (CSP/ESP): seamlessly connecting continuous casting and rolling, eliminating the traditional heating furnace process, and reducing energy consumption by 40% -70%. For example, the ESP production line of Rizhao Iron and Steel has achieved mass production of 0.8mm ultra-thin strip steel, with a yield increase of 1% -2%.

Headless rolling technology: By welding or liquid connection of steel billets, continuous rolling of infinitely long strip steel is achieved, reducing head and tail waste. After applying this technology on the 2250mm production line of Baowu Group Zhanjiang Iron and Steel, the comprehensive yield rate increased to 98.5%.

2. Intelligent control enhances stability

● Industrial Internet and big data: through real-time collection of rolling force, temperature, speed and other parameters, build a digital twin model and optimize the rolling schedule. For example, Hualing Liangang applied AI algorithms to predict roll wear and extended the roll replacement cycle by 20%.

Remote operation and predictive maintenance: Utilizing 5G+AR technology to achieve remote equipment inspection, combined with vibration analysis to predict faults and reduce unplanned downtime. After applying this technology at the Bayuquan branch of Ansteel Group, the overall equipment efficiency (OEE) increased by 5%.

3. Green manufacturing, practicing the "dual carbon" goal

● Ultra low emission transformation: Adopting a combination of technologies such as electrostatic precipitator and wet electrostatic precipitator, the particulate matter emission concentration is reduced to below 10mg/m ³, achieving ultra-low emission standards.

Waste heat recovery and utilization: Through technologies such as heating furnace flue gas waste heat boiler and laminar cooling water waste heat power generation, energy cascade utilization is achieved. The waste heat recovery rate of Shougang Jingtang production line reaches 85%, with an annual reduction of 300000 tons of carbon dioxide emissions.

3、 Market application: Combining high-end and differentiation

1. Automotive field: Lightweight and high reinforcement

High strength automotive panels produced by hot rolling mills (such as DP steel and TRIP steel) are widely used in vehicle structural components, achieving a weight reduction of 15% -30% while improving collision safety. For example, Valin Steel's 1500MPa grade ultra-high strength steel has entered Tesla's supply chain.

2. Energy sector: Corrosion resistance and long lifespan

For oil and gas transmission pipeline steel (such as X80, X100), the hot rolling group uses controlled rolling and controlled cooling (TMCP) technology to refine grain size and improve toughness, meeting the requirements for low-temperature service at -40 ℃. The X80 pipeline steel developed by Bengang has been applied in the West East Gas Pipeline Project.

3. Architecture field: high precision and low cost

The 28mm thick hot-rolled steel coil, through optimized rolling process, has strength and toughness similar to medium thick plates, but with a 10% increase in raw material utilization and a 15% reduction in production costs, making it an ideal alternative material for fields such as bridges and ships.

4、 Future prospects: Technology driven and industrial upgrading

1. Breakthrough in Extreme Specifications

Develop ultra-thin strip steel below 0.5mm and ultra-thin plate rolling technology above 35mm to meet emerging demands such as new energy vehicle battery casings and large construction machinery.

2. Full process intelligence

Build a full process digital factory from steelmaking to rolling, achieving integrated control of quality traceability, energy consumption optimization, and flexible production.

3. Green and low-carbon transformation

Promote hydrogen based direct reduction of iron (DRI) and short process electric furnace technology, combined with carbon capture and storage (CCUS) technology, striving to achieve a 30% reduction in carbon emissions intensity of hot rolling processes by 2030.