Hot Rolling Mill

The operation process of hot rolling mill can be divided into the following core links, which need to be combined with equipment operation specifications and production technology to achieve efficient production:
1. Preparation of slab
Source of raw materials ‌
Slabs are mainly from billets stored in continuous casting workshop or thermal insulation pit. Direct hot charging, thermal insulation pit hot charging or conventional furnace charging method ‌ can be selected according to the production plan.
Pretreatment ‌
The slab should be weighed, measured and positioned, and the surface oxide layer should be removed by the phosphorus removal equipment to ensure the rolling quality ‌.
Second, the heating furnace preheating
Heating temperature control ‌
The slab is heated above the metal recrystallization temperature (usually 1100-1250 ° C) in the heating furnace to improve plasticity and reduce deformation resistance ‌.
Temperature uniformity ‌
It is necessary to ensure that the temperature distribution in the furnace is uniform to avoid cracks or uneven thickness during the rolling process due to temperature difference ‌.
Three, rolling process
Bloom blank ‌
The heated slab goes to the blooming mill for multiple passes rolling, and the thickness and shape are preliminarily adjusted to eliminate casting defects ‌.
Finishing ‌
Through continuous rolling of 7 4-high finishing mill sets, parameters such as roll gap and rolling speed are adjusted to make the steel plate reach the target thickness (can be as thin as a few millimeters) ‌. Finishing speed up to 23m/s, using automatic control system to ensure accuracy ‌.
Exception handling ‌
If there is stuck steel or running steel in rolling, it is necessary to stop immediately to avoid equipment damage or safety accidents ‌.
Fourth, cooling and winding
Cooling control system ‌
After rolling, the steel plate is rapidly cooled by laminar flow cooling device, and the metallographic structure is controlled to optimize the mechanical properties ‌.
Take-up molding ‌
The cooled steel plate is rolled into steel coils by the coiler, or cut into fixed size sheets for easy transportation and subsequent processing ‌.
5. Quality inspection and finished product processing
Online inspection ‌
The dimensional accuracy is monitored in real time by measuring roller, flying shear and other equipment, and the irregular part of the head of the board is removed ‌.
Surface treatment ‌
Some products need to be pickling, oiling and other processes to improve the surface quality to meet the needs of downstream applications ‌.
Safe operation essentials
To avoid high temperature burns ‌, wear protective clothing, gloves, and goggles.
Do not touch the roll or adjust the guide position at the inlet side of the rolling mill when it is running. After troubleshooting, stop the rolling mill and perform ‌.
Avoid back rolling line operation to prevent running steel injury ‌.