Spiculate Bainitic Nodular Cast Iron Rolls(Centrifugal)SGAI can improve the production efficiency of the pre-finishing rolling stand, and reduce downtime during the production process and the frequency of roll replacement, thereby reducing production costs. It has wear resistance and can withstand the friction and wear of metal blanks during high-speed rolling, extending the service life of the roll. SGAI rolls have high strength and toughness and can withstand high pressure and impact loads, ensuring the stability and safety of the rolling process. The pre-finishing rolling stand has high requirements on the cold hardening performance of the rolls. The Spiculate Bainitic Nodular Cast Iron rollers(Centrifugal)SGAI can maintain good hardness and shape stability under high temperatures to ensure the dimensional accuracy of the rolled products. SGAI rolls are suitable for various pre-finishing rolling stands and can meet the pre-finishing rolling needs of metal billets of different sizes and materials. The acicular bainitic ductile iron roll (centrifugal) SGAI has a lower manufacturing cost, but its performance can still meet the requirements of the pre-finishing mill stand and is cost-effective.
Hardness HSD: 55-78
Nickel composition %: 3.01-3.5
Suitable for racks: refined and rolled
Usage: Blooming and slabbing mills; large, medium, small section mills, wire mills, and narrow strip mills;pre-finishing stands of high-speed wire mills.
Bainitic Nodular Cast Iron Rolls (SGA)
| Chemical Composition % | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | C | Si | Mn | P | S | Cr | Ni | Mo | Mg |
| SGAⅠ | 2.90-3.60 | 1.20-2.20 | 0.20-0.80 | ≤0.01 | ≤0.03 | 0.20-1.00 | 3.01-3.50 | 0.50-1.00 | ≥0.04 |
| SGAⅡ | 2.90-3.60 | 1.00-2.00 | 0.20-0.80 | ≤0.01 | ≤0.03 | 0.30-1.50 | 3.51-4.50 | 0.50-1.00 | ≥0.04 |
| Prosperities & Application | ||||||||
|---|---|---|---|---|---|---|---|---|
| Symbol | Hardness | Tensile Strength | Dimension | Application | ||||
| HSD | MPa | MM | ||||||
| SGAⅠ | 55-78 | ≥350 | ￠300-1000 | Blooming and slabbing mills; large, medium, small section mills, wire mills, and narrow strip mills;pre-finishing stands of high-speed wire mills. | ||||
| SGAⅡ | 60-80 | ≥350 | ||||||
SGAI is built around two decisions: the matrix and the casting method. The matrix is spiculate, or needle-like, bainite, a structure known for combining strength with toughness. Fine bainitic needles resist deformation under load, while spheroidal graphite nodules interrupt crack paths and keep the body from becoming brittle. For a stand that sees both heavy pressure and sudden impact, this pairing is a strong foundation.
Centrifugal casting shapes the working layer. Spinning the mold during solidification pushes the melt outward and promotes a dense, uniform shell with fewer internal defects. The roll can therefore present a consistent working surface around its full circumference. Among Nodular Cast Iron Mill Rolls, this combination of structure and process places SGAI in the demanding zone just ahead of the finishing stands.
Nickel at 3.01-3.5% supports the bainitic transformation and improves hardenability, so the structure forms evenly through the working layer. Hardness covers a wide span of 55-78 HSD, which allows the roll to be matched to the specific pass duty and mill practice instead of forcing one fixed level on every stand.
Pre-finishing stands need a roll that hardens reliably without becoming fragile. The bainitic matrix and nickel alloying keep hardness stable from the surface into the usable depth, so passes remain effective after redressing.
Sliding contact with hot, fast-moving stock wears rolls steadily. SGAI resists this attrition, so grooves keep their profile longer and the roll gives predictable tonnage per campaign.
High strength and toughness let the roll carry heavy separating force and absorb the occasional shock from a cold end or uneven billet. This protects against breakage that would stop the line.
The surface holds its hardness and geometry as heat builds up during continuous rolling. Stable grooves lead to stable product dimensions, which supports the tight tolerances that follow in the finishing stands.
Longer service intervals reduce roll changes and idle time. At the same time, production cost for this grade stays below that of many premium materials, so the economics improve on both sides of the ledger.
A dense, evenly wearing roll face is less likely to roughen, which helps keep the rolled surface clean as the stock moves toward final size.
SGAI is most closely associated with the pre-finishing position, but its property balance extends to several mill types:
Here speed, heat, and precision all matter at once. The roll's hardness retention and wear resistance support steady output at high line speed.
In stands that shape angles, channels, and beams, the roll handles uneven loading across complex grooves while holding profile accuracy.
For positions where strength and toughness take priority, the bainitic structure supplies load capacity and resistance to impact.
Intermediate stands benefit from consistent hardness and dependable surface quality.
Stands that bridge roughing and finishing can use the roll's mix of strength and wear resistance.
Across these uses, the roll can process billets of different dimensions and materials, with barrel size and groove design adapted to each mill. Because the hardness range is wide, the exact specification should be chosen according to stand position and product requirements.
It describes the needle-like shape of the bainite in the microstructure. This fine, acicular form contributes to the roll's combination of strength, toughness, and hardness.
Different stands and products call for different balances between wear resistance and toughness. A wider range lets the roll be specified for the duty at hand, with lower hardness favoring impact resistance and higher hardness favoring wear life.
Bainite generally offers a more favorable mix of strength and toughness at high hardness than pearlite. For stands with higher demands, this makes SGAI a stronger choice than standard Nodular Cast Iron Mill Rolls with a pearlitic matrix.
