Rolling rolls strength is the most basic quality index. While meeting the strength requirements, it must also have a certain impact toughness. In order to have sufficient strength of the rolls, it is mainly considered from selecting the material of the rolls and determining the reasonable roll structure and size. Whether the strength is sufficient or not can be determined according to the roll strength calculation. Hardness generally refers to the hardness of the working surface of the roll and is also the main indicator of the roll, which determines the wear resistance of the roll. To a certain extent it determines the service life of the rolls. Strength requirements can be met by material selection and some heat treatment of the roll surface. In addition, when the roll is operated under hot rolling conditions, it should also have a certain degree of wear resistance to protect product accuracy.
Why is it broken?
There are several reasons for the broken roller:
1) The roll is not properly cooled. If the closed water is rolled, the cooling water is supplied too soon too soon.
2) The roller is not installed correctly, resulting in uneven force during operation.
3) The deformation resistance is increased due to the winding roller, the feeding hole, and the excessive rolling deformation; or the rolling temperature is too low, and the rolling force exceeds the strength limit of the roller.
4) The intrinsic quality of the rolls is not good, the original stress is not eliminated or there are casting shrinkage holes; the rolls have low strength in some places, resulting in stress concentration.
5) The groove of the roll is deep, the working diameter of the roll is too small, and the roll strength is insufficient.
The above various conditions will cause the broken roller, but the broken roller is generally caused by a combination of several conditions, and is a process from quantitative change to qualitative change.
In order to avoid unnecessary broken roller accidents and extend the service life of the rolls, technical operation procedures should be carefully implemented to strengthen technical management. It is necessary to carefully analyze the causes and summarize lessons learned from each broken roller accident.