Spheroidal Graphite Cast Iron Rolls
The Spheroidal graphite cast iron roll also called nodular cast iron roll or Ductile Iron Rolls are applied in hardness & composition mills producing different steel products. The cast iron roll is structurally made up of cementite and nodular graphite. Sufficient water cooling is a necessity for satisfactory performance.
The matrix structure varies from Ferrito-Pearlitic, Pearlitic to Bainitic & Martensitic together with different carbide contents and graphite in the form of spheroids/nodules. Some critical grades are heat treated for higher strength.
S.G. Iron Pearlitic Rolls & S.G. Iron Accicular Rolls can be made by alloying with nickel, molybdenum and chromium for added strength and deep hardness penetration.
S.G. Iron Pearlitic Rolls
Pearlitic Spheroidal Graphite Rolls have a thick layer of cast iron with nodular graphite, the name of such roll is based on the fact that the material consists of nodular graphite and carbides in a pearlitic matrix, the softest grades have a pearlitic matrix containing ferrite around the graphite nodules, while the higher hardness grades have a complete pearlitic matrix, the carbide content increases proportionately with the hardness.
S.G. Iron Accicular Rolls
Acicular Spheroidal Graphite Rolls also have a thick layer of cast iron with nodular graphite, here, the name of such roll is based on the fact that the material consists of nodular graphite and carbides in a pearlitic - bainitic matrix, the carbide content is considerably higher in the harder grades than the softer ones.
Chemical Composition
| Material | Hardness (SH-D) | C% | Mn% | Si% | Cr% | Ni% | Mo% | S% | P% |
| S.G. (Pearlitic) | 40-50 | 3.00-3.30 | 0.30-0.60 | 1.50-2.30 | 0.015 MAX | 0.10 MAX | 0.30 MAX | 1.50-2.00 | 0.25-0.40 |
| S.G. (Pearlitic) | 50-60 | 3.00-3.30 | 0.30-0.60 | 1.50-2.30 | 0.015 MAX | 0.10 MAX | 0.30 MAX | 1.50-2.00 | 0.25-0.40 |
| S.G. (Pearlitic) | 60-70 | 3.10-3.50 | 0.50-1.00 | 1.30-1.80 | 0.015 MAX | 0.10 MAX | 0.30-0.80 | 1.50-2.50 | 0.30-0.60 |
| S.G. (Pearlitic) | 70-75 | 3.10-3.50 | 0.50-1.00 | 1.30-1.80 | 0.015 MAX | 0.10 MAX | 0.30-0.80 | 1.50-2.50 | 0.30-0.60 |
| S.G. (Acicular) | 40-50 | 3.00-3.30 | 0.30-0.50 | 1.80-2.30 | 0.015 MAX | 0.80 MAX | 0.20 MAX | 2.00-3.00 | 0.60-0.90 |
| S.G. (Acicular) | 50-60 | 3.00-3.30 | 0.30-0.50 | 1.80-2.30 | 0.015 MAX | 0.80 MAX | 0.20 MAX | 2.00-3.00 | 0.70-1.00 |
| S.G. (Acicular) | 60-70 | 3.10-3.50 | 0.50-0.80 | 1.30-2.00 | 0.015 MAX | 0.80 MAX | 0.30-0.80 | 2.00-3.50 | 0.80-1.10 |
| S.G. (Acicular) | 70-80 | 3.10-3.50 | 0.50-0.80 | 1.30-2.00 | 0.015 MAX | 0.80 MAX | 0.30-0.80 | 2.00-4.50 | 0.80-1.10 |
