By SARJIT ROLLS
Keywords: Spun cast DPIC rolls, SG acicular rolls, Enhanced
carbide rolls, SG Iron
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Pass life of the roll has
become the defining factor for rolls in Rolling mills. A Roll is intended to
have better performance at a sustainable price. A roll manufacturer would agree
that quality comes at a price but just adding alloys into the rolls is not the
right way to go. There needs to be a reasonable understanding of what kind of
an element has what kind of an effect on the wear resistance of the roll and
for what stands.
In this blog I would be
alluding to the work rolls for finishing mills.
Though rolls have come a long
way from the simple static cast Pearlitic structures a technology of the 1950’s
to centrifugally cast double poured solid rolls (1980’s). There was also a time
for shaft fitted double poured barrels but with the increase in production and
subsequently the speed of the mills, the shaft fitted barrels often lead to
slippage causing mill accidents.
To counter this problem spun
cast DPIC solid Rolls are used for finishing stands of rolling mills. They have
the right mix with an adequate hardness of around 80 +/- 2 sH with a bainitic
structure to provide a polish on the rolled product along with the necessary
alloying to have a longer pass life as it portrays properties of increased wear
resistance.
DPIC Rolls can be classified
into 3 main categories: Normal spun cast DPIC rolls with nickel content in range of 2.5 –
4 % and then Enhanced Carbide DPIC with further added alloys in the range of
0.5 - 1% and SG Acicular rolls with the outer working layer made up of highly
alloyed Spheroidal Graphite SG iron
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