The roll is an important part of the rolling mill in the rolling mill. The pressure produced by a pair or group of rolls is used to roll the steel. It mainly bears the influence of dynamic and static loads, wear and temperature changes during rolling.
There are two kinds of rolls: hot roll and cold roll.
The materials of work rolls in common cold rolls include 9Cr, 9cr2,9crv, 8crmov, etc. the cold rolls require surface quenching, and the hardness is hs45~105.
The commonly used materials for hot rolling rollers are 55mn2,55cr, 60CrMnMo, 60simnmo, etc. hot rolling rollers are used in the processing of billet, thick plate, section steel, etc. It bears the strong rolling force, severe wear and thermal fatigue, and the hot roll works at high temperature, and allows the diameter wear within the unit workload, so it does not require surface hardness, but only high strength, toughness and heat resistance. The hot rolling roll is only normalized or quenched as a whole, and the surface hardness is required to be hb190~270. Hardness roll hardness is an indirect physical value, and its level is affected by the internal organizational state of the roll itself, such as the matrix hardness of the roll material, the type and quantity of carbides in the roll material, the residual stress of the roll, and so on; At the same time, because the commonly used shore and Leeb hardness tests for roll hardness testing are rebound hardness tests, they are greatly affected by the state of testing instruments, the psychological factors of operators and other factors. Therefore, both the manufacturing and using departments of rolls need to assign special personnel to be responsible for hardness testing, pay attention to the selection of hardness tester, and the comparison relationship with other hardness should be stable. At the same time, pay attention to the frequent submission and calibration of hardness testing instruments and standard test blocks. Qualified enterprises can promote the use of standard rolls for hardness tester calibration.
Post time: Jul-02-2022