The backup rolls of 4-Hi flat-product rolling stands need to be periodically dressed to eliminate the strain hardened subsuperficial layer generated by continuous co-rotation between these rolls and the work rolls. This procedure is necessary since fatigue cracks can appear in such strain-hardened subsuperficial layers and originate severe spallings in the backup rolls. Their repair could significantly lower their useful life. As these rolls are made of high quality alloy steel or iron, they are very expensive and it is vital that the dressing depth be kept to a minimum but, simultaneously, avoid the presence of excessively fatigued material. This paper shows the principles of a mathematical model that calculates this optimized dressing depth according to the predicted fatigue that the roll was subjected. This algorithm was implemented in an Excel spreadsheet, making data input and calculation easy and quick.
Backup roll; dressing; fatigue
