The operation process of the hot rolling machine can be divided into the following steps, combining the key points of equipment operation and the principles of process control:
1. Pre-operation preparation
Equipment inspection: Confirm the position of the rolls, the alignment of the roll gap, check the hydraulic system, cooling pipes and lubrication status, and clean the guide devices and rollers of the track of debris.
Raw material processing: Check if the steel billet/steel coil has defects such as warping or scratches, use flaw detection tools to inspect the surface of the rolls, and ensure that the diameter difference of the working rolls is ≤ 1mm and the hardness difference is ≤ 3.
Heating control: Heat the steel billet to 1100-1200℃ (the required temperature for hot rolling), use high-pressure water guns to remove the surface oxide layer to ensure the quality of rolling.
2. Rolling process
Parameter setting: Follow the principle of "first wide then narrow", set the initial rolling force to 10-50 tons, and gradually increase it to the target value.
Rolling adjustment:
Plate shape control: Increase the pressure on the side with larger warping, increase the bending force for bilateral warping, and reduce the bending force for middle warping.
Final rolling stage: Through repeated extrusion by more than 6 rollers, make the steel strip reach the target thickness.
Temperature management: The hot rolling needs to be completed within 1 minute to avoid failure of cold rolling due to cooling of the iron material.
3. Finishing and maintenance
Finished product processing: The hot-rolled steel strip is rolled into a steel coil by rotating the disc and sent to the cooling area.
Equipment maintenance: The roll changing cycle is approximately 2500 tons (for the middle roll), after roll changing, the roll gap needs to be recalibrated and a test run is required.
4. Safety regulations
Wear heat-resistant gloves, goggles and anti-collision shoes, and do not cross the running roller track.
In case of emergency, immediately cut off the power supply and use the emergency stop button. Notes: The operation of the hot rolling machine must strictly follow the control of temperature and time. The start-up methods for cold and hot states are different (for example, steam turbines need to distinguish between cold and hot state startup procedures).
