Steel Rolls 'as-cast' without heat treatment are not
suitable for rolling. Dendritic structure, coarse grain, non-homogeneity
and internal stresses make it poor in mechanical properties. So these
rolls are subjected to precisely Comentite/Ferrite more evenly while
retaining the basic Pearlitic structure so important to Alloy Steel
Rolls.
Such rolls have higher strength at cost of hardness decrease compared to
Chill or S G iron Rolls, making them suitable for heavier passes and
severe stress in the roughing & intermediate stands.
Alloy cast Rolls are chiefly applied for the mills where the strength or
biting quality is taken into further consideration than wear resistance.
A wide range of Alloy cast Steel Rolls have been developed to meet
individual applications, depending on their carbon content and heat
treatment.
Alloy steel Base Roll performance in rolling operation is generally
placed in middle way, lying between the quality of Alloy Cast Steel
Rolls and that of S G Iron Rolls.
The rolls are heat treated for many hours under the rigid control of
metallurgical standard. Their resistance to wear and abrasion of the
rolls is quite excellent.
These rolls are incomparable for rolling Rails, Angles, Channels, and
Beams, where deep passes are necessary. They are specially recommended
for high tonnage of Billet, Sheet bar and rails and where very long
rolling period is required. They are extensively used for duty work,
such as blooming and slabbing. |