Pearlitic Ductile Iron Roll III (SGPIII) can provide high-precision rolling to ensure the dimensional accuracy and surface quality of rolled products. SGPIII rolls have good wear resistance and can withstand the friction and wear of metal blanks during high-speed rolling, extending the service life of the rolls. SGPIII rolls can maintain good hardness and shape stability at high temperatures, ensuring the dimensional accuracy of rolled products. Pearlitic Ductile Iron rollers III (SGPIII) can improve the production efficiency of the finishing mill, and reduce downtime during the production process and the frequency of roll replacement, thereby reducing production costs. SGPIII rolls are suitable for various finishing mills and can meet the rolling needs of metal billets of different sizes and materials. Very cost effective.
Hardness HSD: 62-72
Nickel composition %: 2.51-3.0
Suitable for racks: Refined and rolled
| 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 | |||||
In a rolling line, the final stands decide what the customer actually receives. Thickness tolerance, section shape, and surface appearance are all fixed here, and nothing downstream can fully correct them. SGPIII is a pearlitic ductile iron grade built for this responsibility, and it is a precision-oriented member of the Finishing Mill Rolls family.
Its working hardness of 62-72 HSD is noticeably higher than that of roughing grades. Combined with nickel at 2.51-3.0%, the pearlitic matrix becomes finer and more uniform, and hardness holds up deeper into the barrel. Spheroidal graphite remains in the structure to keep the roll from turning brittle, so the grade retains a margin of strength even at a hardness suited to fine work.
Tight tolerances depend on grooves and barrel surfaces that change as little as possible. Because SGPIII resists gradual metal loss, the gap and pass geometry set at the start of a campaign stay close to target for longer. Operators spend less time compensating for drift, and product dimensions stay consistent from the first piece to the last. The same hard, even surface limits the marks that a rough or pitted roll would leave on the product, supporting a cleaner finish.
Finishing stands often run at high speed with continuous contact between roll and hot stock. The surface of SGPIII keeps its hardness as temperature rises, so it does not soften and flatten out during long runs. Wear stays slow and even rather than patchy, which extends each campaign and makes roll life easier to forecast.
Longer campaigns reduce changeovers, cutting idle time and handling effort. As a pearlitic ductile iron grade, it is cheaper to produce than many premium alternatives, so the cost per ton rolled drops without the need for exotic materials. Mills gain better value from each roll while protecting product quality.
Where stock moves quickly through successive stands, the roll surface faces intense sliding and heat. A wear-resistant, temperature-stable face keeps the process steady and the output uniform. For this kind of duty, dependable Finishing Mill Rolls are a direct contributor to line efficiency.
Mills that change products often benefit from rolls that can be re-dressed and still offer a hard working surface. Billets of different sizes and materials can be handled, with groove layouts and roll dimensions matched to each case.
For customers who specify tight dimensional limits or demanding surface standards, the stability of the roll provides a stronger base for meeting requirements consistently, order after order.
SGPIII belongs in finishing positions, where precision outweighs impact resistance. Final grade choice should consider the stand position, rolling speed, product range, and cooling conditions of the mill.
Higher nickel, at 2.51-3.0%, refines the matrix and improves hardenability, which supports the greater hardness needed for finishing duty. Roughing grades use less nickel because they prioritize toughness against heavy impact.
It is designed for finishing, where reductions are lighter and precision is the priority. Early stands that face heavy impact are better served by a tougher, lower-hardness grade.
Even cooling water distribution, correct alignment, well-maintained guides, regular surface inspection, and timely pass dressing all make a difference. With good practice, the grade can hold its accuracy across the entire campaign, which is what makes quality Finishing Mill Rolls pay off.
