Spheroidal Graphite Cast Iron (S G Iron) or Ductile Iron is considered as one of the most versatile roll materials now a days. It is produced by a small proportion of magnesium added to the melt as nickel-magnesium or alternative alloy, or as pure magnesium. In S G Iron Roll, the free carbon takes the shape of spheroidal or nodules, thereby eliminating the notch effect of flake graphite and improving upon the mechanical properties of the cast iron.
S.G Iron Rolls are so superior in wear resistance to that of Cast Steel Rolls that they are specially adapted for rough and intermediate plate mills and rod , bar mill rough. As a result of the spheroidal form of the graphite, S G Iron Rolls are much strong than rolls of the clear-chill type and the gradual fall in hardness is an added advantage. As such, these rolls are particularly suitable for Skelp and Strip Mills, also Bar Billet Mills, and are being increasingly used for other applications.