During the manufacture of pipes and tubing, roll marks can appear as a result of the speed difference between the throat diameter — the smallest diameter of the roll and also the drive point —and the outer flange rolls within a given pass on the mill. During production, the surface speed at the throat area of the roll is lower than the surface speed at the largest diameter, which causes the roll to leave marks on the end product.
Floating flange rolls have a keyed center piece that turns at the speed of the mill. The two outside pieces are able to spin freely, allowing them to turn at the speed of the material being formed as it moves through the mill. Because the material and outside rolls are move at the same speed, roll marks are eliminated.