In cold rolling production, roll has a significant impact on strip yield, surface quality and ton steel cost. Roll defects not only reduce the yield, but also may lead to equipment damage. Therefore, steel mills must pay attention to the use and maintenance of rolls, and strive to reduce the consumption of rolls.
Common roll defects
The following defects often occur in the rolling process:
Vibration mode
The common light and dark stripes on the surface of the strip are called strip tremors. The practice shows that this vibration comes from the vibration of the roll. The main reasons include vibration of the grinding wheel spindle, poor shape of the grinding wheel, and poor contact of the roll support.
Roll mark
Roll marks are characterized by pinholes and dents on the roll surface, which are usually caused by foreign bodies entering the roll bite area. Timely identification of the source of foreign matter and improvement of lubrication and cooling conditions can effectively prevent such defects.
Cutwork
The cut is caused by the mismatch between the roll speed and the wheel speed. The preventive measures for this defect include reasonable configuration of equipment parameters and regular inspection of the sharpness of the grinding wheel.
Crack
Cracks are mostly caused by local stress concentration, which is common in the rolling process. Timely treatment of cracks can avoid more serious defects and material losses.
Mince
Broken meat is the phenomenon of the surface of the roll peeling, mainly due to the thermal shock or high cycle fatigue produced during the rolling process. Regular inspection and treatment of the peeling area can effectively extend the service life of the roll.
Handling measures
For different types of defects, steel mills can take the following treatment measure.
Striation
For obvious vibromarks, coarse grinding should be selected for treatment, while non-obvious vibromarks can be solved by semi-coarse grinding.
Roll mark removal
According to the degree of roll marks, the method of grinding or turning is used to remove.
Prevent cutting
Optimize roll speed and grinding wheel parameters to ensure that the grinding wheel is sharp and free of defects, which can effectively reduce the occurrence of knife scratches.
Treatment crack
The cracks found are promptly ground and inspected to ensure that the cracks are completely removed and prevent their expansion.
Repair spalling
The combined method of rough grinding and flaw detection is used to deal with the peeling of the roll surface to ensure that the roll keeps in good working condition.
Conclusion
In cold rolling production, roll defects directly affect product quality and production efficiency. Steel mills need to attach great importance to roll maintenance and management, take effective measures to reduce the incidence of defects. Through the rational use and timely maintenance of rolls, steel mills can significantly improve the yield, reduce production costs, and lay a solid foundation for the development of enterprises.
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