Roll family 07 · Roughing · intermediate
Spheroidal Graphite Iron Rolls (SGI)
SG iron combining strength with thermal resistance.
About this roll
SG iron rolls: the material
SG (ductile) iron is one of the most versatile roll materials today, with greatly improved properties including tensile strength above 40 kg/mm² against 20–30 kg/mm² for cast iron. Specifically good for small section and flat rolling, and most suitable for heavier sections where added strength and depth of hardness are required. Stand-cast acicular SG iron is employed for special-purpose rolls such as pilger rolls.
Where it works
Its place in the mill
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Roughing: used here
Heavy passes, high loads
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Intermediate: used here
Shape and size take form
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Finishing: not usual here
Final size and surface
Metallurgy
Composition and properties
Ranges from our grade sheets. The exact composition is set for each order.
| Grade | C % | Si % | Mn % | Cr % | Ni % | Mo % | U.T.S. kg/mm² | Elong. % | Shore C (HSC) |
|---|---|---|---|---|---|---|---|---|---|
| SG Iron — Pearlitic | 2.90-3.40 | 1.40-2.50 | 0.50-0.70 | 0.15-0.35 | 1.50-2.00 | 0.25-0.60 | 38-62 | 0.50-0.80 | 45-55 |
| SG Iron — Pearlitic (hard) | 2.20-3.50 | 1.20-1.90 | 0.60-0.90 | 0.25-0.50 | 1.50-2.50 | 0.25-0.60 | 38-62 | 0.50-0.80 | 55-65 |
- Alloy cast steel 30–45
- Grey iron core 35–45
- SG iron core 35–45
- Adamite steel base 45–55
- SG pearlitic 45–55
- SG pearlitic (hard) 55–65
- Definite chill 55–70
- Indefinite chill 55–75
- SG acicular 65–75
- Non metal 65–75
- Definite chill (hard) 70–75
- DP shell I 70–75
- SG acicular (hard) 75–80
- DP shell II 75–80
- HSS I 75–80
- HSS II 75–80
- DP shell III 80–85
Recommended use
Where we recommend it
Mills and stands where this roll is the usual choice, with the barrel hardness we recommend.
| Rolled product | Type of mill | Stand and barrel hardness, Shore C |
|---|---|---|
| Flat products for steel mills | ||
| Cold Strip | 4 Temper |
|
| Plates | 2 High |
|
| Plates | 3 High |
|
| Plates | 4 High |
|
| Sheet | 2 & 3 High |
|
| Shaped products for steel mills | ||
| Billets, Bars & Round | 2 & 3 High |
|
| Medium Sections | 2 & 3 High |
|
| Light Section Bar | 2 & 3 High |
|
| Billets | Continuous |
|
| Medium & Light Sections | Continuous |
|
| Wire Rod | Continuous |
|
| Rolls for non-ferrous metals | ||
| Slabs | 4 High Roughing |
|
| Slabs | 4 High Finish |
|
| Shaped Products | 2 & 3 High |
|
| Shaped Products | 2 High |
|
Production process
From melt to mill
Static cast rolls
Cast in one piece in a chill mould.
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Charge mix
Pig iron and foundry returns, weighed for each heat.
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Melting
Tapped into the ladle once the chemistry is right.
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Static casting
Poured into a chill mould that freezes a hard working face.
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Heat treatment
Hardening and tempering on a controlled temperature cycle.
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Rough machining
Barrel and necks turned close to size.
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Necks & wobblers
Necks, faces and wobblers shaped to the mill's drawing.
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Grinding
A final grind brings the barrel to size and finish.
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Testing
Shore hardness mapped across the barrel.
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Certificate & dispatch
Rested on timber saddles and strapped, with its certificate.
- Your roll drawing, or barrel and neck sizes
- Mill type and the stand for the roll
- Material rolled and the pass or groove
- Quantity and the date you need it
Our range
Other roll families
- 01 Clear chill rolls Finishing stands
- 02 Alloy cast steel rolls Roughing stands
- 03 Indefinite chill rolls Intermediate · finishing
- 04 Adamite rolls Roughing · section mills
- 05 Multi rolls Mixed schedules
- 06 Forged rolls Cold rolling · high duty
- 08 SGACC rolls Intermediate · finishing
- 09 HSS rolls Intermediate · finishing
- 10 Metal rolls General applications
Need this roll for your mill?
Send your drawing or roll size — we will quote by return.