Study on Flakes of a Steel Roller

Abstract

The study of flakes is rare, but once it occurs, the material will suddenly burst, and the consequences are very serious. In this paper, the surface burst reason of a steel rolling mill backup roll was analyzed. The backup roll material meets a criterion of 86CrMoV7 ingredient, there are silver gray round and oval defects on macro fracture surface, visually there are more silver gray white fisheyes on the debris of the failure roller. Microscopic fracture morphology has obvious brittle fracture characteristics. The hydrogen of local surface area measured failure roller reaches 9×10−4 %, more than three times the allowable amount that flake no appear. Failure roll hairline cracks, or snow flakes assessed according to the standard are grade 2-3, which is a more serious flake level. The analysis results show that the flake is the main cause of the backup roll premature failure.