Maintenance Method of Medium and Small Centrifugal Roll


Time:

2021/12/24

The causes of early failure accidents such as abnormal skin explosion of small and medium-sized centrifugal rolls are very complex, which may be directly related to the internal quality of the rolls (including metallurgical defects such as billets, casting, forging, heat treatment, etc.). This is also closely related to our defects in the use and maintenance process. If a good quality roller is not operated and maintained properly, accidents are prone to occur. Now we have improved the acceptance requirements of road rollers, and those that do not meet the acceptance standards of road rollers will be rejected. In addition to strict control of incoming acceptance, but also to strengthen the use of roller and maintenance management.

Medium and small centrifugal rollThe causes of early failure accidents such as abnormal skin explosion are very complex, which may be directly related to the internal quality of the roll (including metallurgical defects such as billet, casting, forging, heat treatment, etc.). This is also closely related to our defects in the use and maintenance process. If a good quality roller is not operated and maintained properly, accidents are prone to occur. Now we have improved the acceptance requirements of road rollers, and those that do not meet the acceptance standards of road rollers will be rejected. In addition to strict control of incoming acceptance, but also to strengthen the use of roller and maintenance management.

中小型离心轧辊维护方法

Rolls for cold-rolled sheets are usually forged from high-carbon chromium steel, chromium-molybdenum steel or chromium-molybdenum-vanadium steel, commonly known as forged steel cold rolls. The working conditions of the rollers are very poor. In the rolling process, it is subjected to compressive stress, bending stress, torsion stress, contact fatigue stress and thermal fatigue stress. In order to make the rolled plate achieve the specified dimensional accuracy and better surface roughness, the surface of the roller body is required to have hardness and hardness uniformity. Due to the continuous rolling operation of small and medium-sized centrifugal rolls, the surface is worn, and it is easy to form orange peel defects or cracks, which often need to be repaired before they can be used again. Therefore, it is also requiredMedium and small centrifugal rollIt has a deep effective hardening layer depth. In order to make small and medium-sized centrifugal rolls have these basic properties, in the process of manufacturing, the alloy steel rolls are subjected to water spray quenching and low temperature tempering, so that there is a high residual internal stress inside the small and medium-sized centrifugal rolls. When the combined effect of residual internal stress and rolling stress exceeds the fatigue strength of the roll, early failures such as surface fatigue cracks, spalling or roll fracture will occur, which will seriously affect the service life of the roll.

The technical requirements for the surface hardness of the cold rolling work roll are generally between HS85-95 and 90, the rough rolling is 85-90, and the finish rolling is 90-95. The intermediate roller is a HS80-85 roller and the support roller is a HS65-70 roller. The hardness of the backup rolls of a continuous rolling mill can be increased correspondingly, but it should not be higher than HS75. After quenching,Medium and small centrifugal rollThe surface is brittle and hard, the impact resistance is poor, and severe collision is avoided.