Roll defect repair and grinding countermeasures

From August 2015 to April 2016 unplanned roll replacement statistics can be seen accident rolls accounted for 69% of the total roll replacement. Therefore, after the occurrence of rolling accidents, timely and correct treatment of rolls can minimize the unnecessary damage to the rolls, extend the service life of the rolls and reduce roll consumption.

The following briefly introduces several common accidents roll treatment:

1 Thermal cracks

Thermal cracks, mostly for the card steel or pile of steel after the accident, the roll cooling and heating.

Treatment: R1 and F1-F4 rolls in the premise of ensuring smooth rolling, can be used with hot cracked rolls on the line, and cracks are closed (closed cracks do not extend, but with the use of time to extend), cracks will be gradually eliminated.

2 Roll sticking steel

Rolls stick to steel, dumping or pile of steel accident caused by the roll sticking with steel.

Processing method: roll roll body strip steel adhesion folding serious, large area, thickness of more than 3mm need to be adhered to the strip first turning off. Adhesion of the iron turning off the roll body after checking the surface, if there are cracks and flaking (meat) depending on the degree of damage to determine the depth of cutting, to ensure that the elimination of defects without increasing the excessive roller consumption.

3 Work roll body edge spalling

The edge of the work roll body spalling, roll shoulder stress concentration.

Treatment: Since the shoulder of the roll is not in direct contact with the steel plate, the cracks can be removed from the peeling part, grinding chamfering, and adjust the contact with the support roll chamfering and angle to improve the stress distribution of the roll body.

4 Support roller defects

Support roller defects, support rollers are not in direct contact with the strip and the hardness of the work roll relative to the lower, but the price is expensive, so the use of conventional repair and grinding methods is not appropriate.

Treatment: when the damage is in the roll edge, when grinding the appropriate increase in the length of the end of the chamfer. Defective residue is handled with an angle grinder and will be rounded around the excessive, to prevent flaking defects from spreading further. Damage in the middle of the roll, according to the conventional grinding and then the same with the angle grinder and the defects around the rounded smooth excess.

Leave a Reply

Your email address will not be published. Required fields are marked *