A Comprehensive Analysis Of The Working Principle Of The Hot Rolling Machine

I. Overview of Hot Rolling Process
The hot rolling machine is a core equipment that undergoes continuous plastic deformation of steel billets at high temperatures (typically 900-1250°C). Its working principle can be summarized as three major stages: "heating - rolling - controlled cooling". Compared to cold rolling, hot rolling can significantly reduce the metal deformation resistance and achieve efficient production of large-sized steel.
II. Core Work Process
Heating Stage
The continuous casting billet is uniformly heated to above the austenite transformation temperature in a stepwise heating furnace, eliminating internal stress and optimizing plasticity. Modern heating furnaces use intelligent control systems for air-fuel ratio, reducing energy consumption by 15-20%.
Coarse Rolling Process
Composed of 4-6 universal rolling mills, it compresses the steel billet thickness to the target value of 1/3 through a combination of vertical and horizontal rolls. Dynamic variable specification technology (DSC) is adopted to achieve precise control of thickness within ±0.5mm.
Fine Rolling System
It uses a 7-stand continuous rolling unit, equipped with a hydraulic AGC thickness automatic control system. The final rolling temperature is strictly controlled at 850 ± 20°C to ensure the austenite grain size within the range of 5-15 μm.
Layered Cooling
Through ultra-fast cooling (UFC) technology, a cooling rate of 20-30°C/s is achieved in the conveying roller section, precisely controlling the proportion of phase transformation structure.
III. Key Technical Features
Plate Shape Control: Adopting a combined technology of bending rolls and shifting rolls, the plate shape qualification rate is increased to over 98%
Temperature Compensation: Dual systems of infrared temperature measurement and model prediction, with temperature fluctuations controlled within ±10°C
Intelligent Rolling: Based on industrial big data, self-learning models are used to achieve a rolling force prediction error of <3%