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Graphite steel rolls are composed mainly of pearlite with spherical graphite and some carbide. Graphite steel rolls are stronger than cast iron rolls and harder than other steel rolls. The feature of graphite rolls that is better resistance to fire crack and scale adhesion.
Graphite steel roll
Graphite steel rolls are composed mainly of pearlite with spherical graphite and some carbide. Graphite steel rolls are stronger than cast iron rolls and harder than other steel rolls. The feature of graphite rolls is better resistance to fire cracking and scale adhesion.
Technical Specification
Below is a reference presentation for the main material direction, technical range, and service position of Graphite Steel Rolls. Final specification should be confirmed according to drawing, line condition, and target performance.
Chemical Composition and Physical Properties
| Symbol | C | Si | Mn | Cr | Ni | Mo | Barrel Hardness HS | Roll Neck Hardness HS | Tensile Strength MPa |
|---|---|---|---|---|---|---|---|---|---|
| GS140 | 1.30-1.50 | 1.30-1.60 | 0.50-1.00 | 0.40-1.00 | - | 0.20-0.50 | 36-46 | ≤46 | ≥540 |
| GS150 | 1.40-1.60 | 1.00-1.70 | 0.60-1.00 | 0.60-1.00 | 0.20-1.00 | 0.20-0.50 | 40-50 | ≤50 | ≥500 |
| GS160 | 1.50-1.70 | 0.80-1.50 | 0.60-1.00 | 0.50-1.50 | 0.20-1.00 | 0.20-0.80 | 45-55 | ≤50 | ≥500 |
| GS190 | 1.80-2.00 | 0.80-1.50 | 0.60-1.00 | 0.50-2.00 | 0.60-2.20 | 0.20-0.80 | 50-65 | ≤50 | ≥450 |
Recommended Applications
- Intermediate stands of long product mills.
- Section and bar rolling positions.
- Grooved roll applications requiring stable wear performance.
- Thermally loaded rolling service conditions.
- Positions requiring steel-grade toughness and practical service life.
Product Features
- Good thermal stability with reliable toughness.
- Stable hardness performance with practical wear resistance.
- Suitable for grooved roll applications in section and bar mills.
- Balanced performance for rolling positions requiring both strength and wear life.
Enhanced ICDP rolls are developed based on conventional ICDP rolls with upgraded microstructure performance. The matrix mainly consists of bainitic and martensitic structures with Fe3C and MC carbides uniformly distributed throughout the material, together with fine free graphite evenly dispersed in the matrix.
The rolls are double tempered to minimize retained austenite and achieve an optimized hardness level together with balanced residual stress control. EN-ICDP rolls are especially suitable for applications requiring improved wear resistance, thermal stability, and longer campaign life under high-speed rolling conditions.
Chemical Composition
| Symbol | C | Si | Mn | Cr | Ni | Mo | V | W | Nb |
| EN-ICDP | 2.90-3.60 | 0.60-1.50 | 0.40-1.20 | 1.00-2.00 | 3.01-4.80 | 0.20-2.00 | 0.20-2.00 | 0.00-2.00 | 0.00-2.00 |
Physical Properties
| Symbol | Barrel Hardness | Roll Neck Hardness | Tensile Strength |
| EN-ICDP | 77-85 HS | 32-45 HS | ≥400 MPa |
Recommended Applications
- Hot strip finishing stands.
- Selected roughing and intermediate work roll positions.
- Applications requiring improved strip surface control.
- High-speed flat product production lines.
- Campaign life improvement projects.
Product Features
- Improved wear resistance compared with conventional ICDP rolls.
- Enhanced thermal stability and rolling consistency.
- Optimized carbide distribution and hardness retention.
- Suitable for demanding high-speed finishing applications.
- Reliable performance under long rolling campaign conditions.
Alloy cast steel rolls contain lower carbon content than other cast rolls, including adamite rolls, high-chromium steel rolls, and graphite steel rolls. This structure provides excellent toughness and stable performance under heavy rolling conditions.
The alloy cast steel rolls are produced from high-quality molten steel with advanced casting and heat treatment processes. They offer good wear resistance, fire-crack resistance, and mechanical strength, making them suitable for roughing and backup applications in different rolling mills.
Enhanced High Chromium Iron Rolls are widely used in early finishing stands of hot strip mills, skin pass stands, and finishing stands of small section mills. The high chromium content in the shell material, together with the absence of free graphite, provides excellent wear resistance and stable rolling performance under demanding conditions.
Different carbide structures combined with high hardness and tempered martensitic microstructure ensure superior mechanical properties and extended service life. Enhanced HiCr rolls are additionally alloyed with elements such as V, W, and Nb to increase eutectic carbide hardness and significantly improve rolling performance.
High Chromium Steel Rolls are similar to HiCr cast iron rolls but contain lower carbon content ranging from 1.0% to 1.8%. Lower carbon grades are true steel grades without eutectic carbides, while higher carbon grades contain partial eutectic carbides. These rolls are suitable for roughing stands of hot strip mills, Steckel mills, and selected early finishing positions.
Chemical Composition
| Symbol | C | Si | Mn | Cr | Ni | Mo | V |
| HCr I | 2.30-3.30 | 0.30-1.00 | 0.50-1.20 | 12.00-15.00 | 0.70-1.70 | 0.70-1.50 | 0.00-0.60 |
| HCr II | 2.30-3.30 | 0.30-1.00 | 0.50-1.20 | 15.01-18.00 | 0.70-1.70 | 0.70-1.50 | 0.00-0.60 |
| HCrIII | 2.30-3.30 | 0.30-1.00 | 0.50-1.20 | 18.01-22.00 | 0.70-1.70 | 1.51-3.00 | 0.00-0.60 |
| HCrS | 1.00-1.80 | 0.40-1.00 | 0.50-1.00 | 8.00-15.00 | 0.50-1.50 | 1.50-4.50 | - |
Physical Properties
| Symbol | Barrel Hardness | Roll Neck Hardness | Tensile Strength |
| HCr I | 60-75 HS | 32-45 HS | ≥500 MPa |
| HCr II | 65-80 HS | 32-45 HS | ≥500 MPa |
| HCrIII | 75-90 HS | 32-45 HS | ≥600 MPa |
| HCrS | 70-85 HS | 35-45 HS | ≥700 MPa |
Product Features
- High chromium alloy structure with excellent wear resistance.
- Tempered martensitic matrix for improved mechanical properties.
- Enhanced crack resistance and thermal stability.
- Suitable for demanding hot strip and plate mill applications.
- Available for roughing, intermediate, and selected finishing positions.
HSS Rolls, also known as High Speed Steel Rolls, are manufactured by vertical centrifugal casting technology. The core material is nodular iron with excellent toughness, while the shell material is HSS with high hardness and superior wear resistance under demanding rolling conditions.
The shell structure mainly consists of tempered martensite and bainite with abundant MC, M2C, and M6C carbides uniformly distributed in the matrix. Thanks to the advanced heat treatment process, the microstructure remains stable at high rolling temperatures with minimal hardness drop until the surface temperature exceeds 550°C.
The working layer hardness generally reaches 80-85 HSC with uniform hardness distribution throughout the shell layer. LONSUN has developed different HSS grades according to different mill applications:
- HSS-IM — intermediate stand replacement for nodular rolls.
- HSS-DB — dogbone pre-slitting stand applications.
- HSS-ST — slitting stand service.
- HSS-F — pre-finishing and finishing stands.
Chemical Composition
| Symbol | C | Si | Mn | Cr | Ni | Mo | V | W | Co | Nb |
| HSS | 1.50-2.20 | 0.30-1.00 | 0.40-1.20 | 3.00-8.00 | 0.00-1.50 | 2.00-8.00 | 2.00-9.00 | 1.00-8.00 | 1.80-8.00 | 0.50-5.00 |
Physical Properties
| Symbol | Barrel Hardness | Roll Neck Hardness | Tensile Strength |
| HSS | 75-95 HS | 30-45 HS | ≥750 MPa |
Recommended Applications
- Work rolls for finishing stands of hot strip mills.
- Rolls for universal section mills.
- Rolls for intermediate stands, pre-finishing stands, and finishing stands of bar mills.
- Rolls and rings for pre-finishing and finishing stands of high-speed wire rod mills.
- Rings for KOCKS mills.
- Rings for seamless steel pipe mills.
Product Features
- Excellent wear resistance under high-speed rolling conditions.
- Stable hardness retention at elevated rolling temperatures.
- Uniform carbide distribution for improved rolling stability.
- Suitable for hot strip mills, bar mills, wire rod mills, and seamless pipe mills.
- Available for roughing, intermediate, pre-finishing, and finishing applications.