Figure 10: PDT™ Rsk evolution
It is generally considered that negative skew (less
protruding peaks) and increased bearing area on the
work roll texture improves work roll life, which is
confirmed in figures 9 and figure 10. As the roll wears
and the skew, on the roll, becomes less positive and
rate of wear in figure 9 decreases. Unfortunately,
producing negative skew on the work roll to improve
the roll life produces positively skewed roll sheet
texture which is known to be detrimental to forming
and painting. PDTTM textured rolls were able to
produce negatively skewed strip surface whilst
significantly increasing roll life.
Similar results have also be achieved in the 5th stand
of the tandem mill, where the roll Ra was reduced
from typically 5.5 μm for EDT work rolls to 4.5 μm for
PDTTM work rolls to achieve the same rolled sheet Ra
and useable roll life was increased by a minimum of
30%. The transfer of Rpc was again 1:1 in the 5th
stand of the tandem mill, whereby a work roll Rpc of
55 peaks/cm produces the equivalent on the rolled sheet