SGI Pearlitic Rolls

Spheroidal graphite: one of the most versatile roll materials.

Hardness: 40-75 Shore D
Shop colour code: SGI

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Spheroidal graphite cast iron, also called SGI or ductile iron, is considered one of the most versatile roll materials today. It is produced by adding a small proportion of magnesium to the melt, as a nickel-magnesium or other alloy, or as pure magnesium.

In S.G. iron rolls, the free carbon takes the shape of spheroids, or nodules. This eliminates the notch effect of flake graphite and improves the mechanical properties of the cast iron.

Nodular graphite eliminates the notch effect of flake graphite, improving mechanical properties.

Chemical composition

Hardness	C	Mn	Si	P	S	Ni	Cr	Mo	UTS
40-50	3.0/3.3	0.3/0.6	1.5/2.3	0.10 max	0.015 max	1.5/2.0	0.30 max	0.25/0.4	50-65
50-60	3.0/3.3	0.3/0.6	1.5/2.3	0.10 max	0.015 max	1.5/2.0	0.40 max	0.25/0.4	50-60
60-70	3.10/3.50	0.5/1.00	1.3/1.8	0.10 max	0.015 max	1.5/2.5	0.3/0.8	0.3/0.6	50-60
70-75	3.10/3.50	0.5/1.00	1.3/1.8	0.10 max	0.015 max	1.5/2.5	0.3/0.8	0.3/1.6	40-60

Percentages by weight. Hardness in Shore D. UTS in kgf/mm².

In the works

Long machine shop hall under a yellow Prince Steel Industries EOT crane, with yellow-coded rolls on the floor — Machine shop hall under the EOT crane

Close view of polished steel rolls with stepped necks and wobblers — Polished rolls with stepped necks

Analyst in a white helmet reading a spectrometer report at the workstation — Reading the melt: spectrometer analysis

Lathe number 23 turning a long roll with an operator in the background — Lathe no. 23 at work

Related rolls

SGISGI Bainitic Acicular RollsSGI alloyed with nickel and molybdenum to form an acicular structure as cast. For heavier sections that need added strength and depth of hardness.

ForgedForged RollsCarbon, alloy and stainless steel rolls, hammered to shape and heat treated. Up to 30″ diameter and 10 MT finished weight.

Solid ChillClear Chill RollsClear (definite) chill cast iron rolls with a hard, graphite-free working surface. Excellent work rolls for 2-Hi, 3-Hi and 4-Hi mills.