Pearlite ductile iron rolls have high strength and toughness, can withstand high pressure and impact loads, and are not prone to breakage or deformation, ensuring the stability of rolling. Pearlite ductile iron roll I is suitable for rough rolling mills and can meet the rough rolling needs of metal billets of different sizes and materials, including steel billets, aluminum billets, etc. Compared with some more expensive roll materials, pearlitic ductile iron rolls have lower manufacturing costs, but their performance can still meet the requirements of roughing mills and are cost-effective. Pearlite ductile iron rollers can improve the production efficiency of the roughing mill, and reduce downtime during the production process and the frequency of roll replacement, thereby reducing production costs. Due to its wear resistance, high strength, good chilling and hardening properties, and cost-effectiveness, it plays an important role in roughing mills and is widely used in the metal processing industry.
Hardness HSD: 45-55
Nickel composition %: 1.5-2.0
Suitable for racks: Roughing
Usage: Roughing and slabbing mills; large, medium section mills, wire mills, and narrow strip mills.
| Chemical Composition% | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | C | Si | Mn | P | S | Cr | Ni | Mo | Mg |
| SGPⅠ | 2.90-3.60 | 1.40-2.20 | 0.40-1.00 | ≤0.15 | ≤0.03 | 0.10-0.60 | 1.50-2.00 | 0.20-0.80 | ≥0.04 |
| SGPⅡ | 2.90-3.60 | 1.20-2.00 | 0.40-1.00 | ≤0.15 | ≤0.03 | 0.20-1.00 | 2.01-2.50 | 0.20-0.80 | ≥0.04 |
| SGPⅢ | 2.90-3.60 | 1.00-2.00 | 0.40-1.00 | ≤0.15 | ≤0.03 | 0.20-1.20 | 2.51-3.00 | 0.20-0.80 | ≥0.04 |
| Prosperities & Application | |||||||
|---|---|---|---|---|---|---|---|
| Symbol | Hardness | Tensile Strength | Dimension | Application | |||
| HSD | MPa | MM | |||||
| SGPⅠ | 45-55 | ≥450 | ￠300-1350 | Roughing and slabbing mills; large, medium section mills, wire mills, and narrow strip mills. | |||
| SGPⅡ | 55-65 | ≥450 | |||||
| SGPⅢ | 62-72 | ≥450 | |||||
SGPI is a pearlitic ductile iron roll designed for the first stands of a rolling line, where stock is at its thickest and its behavior is hardest to predict. A strong pearlitic matrix carries the load, and spheroidal graphite nodules keep the body ductile. That pairing is what makes it a dependable option among roughing mill rolls.
Working hardness is set at 45-55 HSD. This moderate level is deliberate. Pushing surface hardness higher increases the risk of spalling when a heavy bite lands on the roll, so this range favors strength, grip, and resistance to deformation over maximum hardness. Nickel at 1.5-2.0% refines the pearlite and improves hardenability, which spreads strength more evenly from the surface inward and supports toughness at the same time.
Roughing stands rarely offer gentle conditions. Entry shock, uneven billet temperature, scale, and large reductions often arrive together. SGPI is designed so the roll absorbs these events instead of cracking under them.
The ductile body absorbs impact at the moment the stock enters the pass. Sudden torque peaks and off-center bites are less likely to start cracks, which lowers the chance of an unplanned roll failure.
High strength means the roll resists bending and permanent distortion during hard reductions. Roll gaps stay predictable, and the stock leaving the stand holds a more consistent thickness and width.
The pearlitic structure wears gradually and uniformly. Pass profiles keep their intended geometry longer, which means fewer corrective adjustments between campaigns.
A moderately hard working face maintains the friction needed to draw heavy billets into the pass. This supports smooth entry and reduces slipping at the start of each reduction.
Fewer roll changes mean less stand downtime and less handling work. Over a full production year, this adds up to measurably higher effective rolling time.
Pearlitic ductile iron costs less to manufacture than many premium roll materials, yet it fully meets the demands of roughing duty. Roll cost per ton stays low without trading away safety margin.
Roughing and slabbing mills. These are the primary home of SGPI. Large initial reductions on slabs and blooms demand a roll that tolerates high separating force and rough surface conditions.
Large and medium section mills. In breakdown stands that shape heavy structural profiles, the roll must carry uneven loads across deep grooves. Its strength and toughness suit this duty well.
Wire mills. Early stands that reduce billets to a workable size benefit from its resistance to shock and its stable pass geometry.
Narrow strip mills. For the initial stands of strip lines, SGPI offers dependable strength and predictable wear.
In terms of stock, the roll can process billets of varied dimensions, including steel and non-ferrous material, with groove layouts and roll dimensions adapted to each mill's practice.
Roughing duty involves heavy impact and high pressure. A moderate hardness paired with strong pearlitic structure gives better resistance to chipping and deformation than a harder but more brittle surface would.
It is positioned for roughing and early-stage stands. Finishing positions typically need higher surface hardness and finer wear control, so a different roll grade is usually more appropriate there.
For roughing work, its strength, toughness, and wear behavior are fully adequate. The lower manufacturing cost translates into a lower cost per ton rolled, which is the figure that matters most to most mills.
