1. Specifications & Capability
FUSHUN METAL forges intermediate rolls in Cr3- and Cr5-series steel, 400-900 mm body diameter, for the intermediate stands of tandem cold strip mills. Rolls are supplied as rough-machined blanks or finished rolls to the mill’s specification.
The rolls are induction hardened to a controlled surface hardness and hardening depth, giving the wear resistance and spalling resistance the intermediate stand requires while keeping a tough core.
| Grade | Standard | Hardening |
|---|---|---|
| Cr3 type (MC3) | User specification | Induction hardened |
| Cr5 type (MC5) | User specification | Induction hardened |
2. Components & Service Conditions
The intermediate roll sits between the work roll and the back-up roll in a multi-roll cold mill stand, transmitting and distributing the rolling load. It is not the roll that touches the strip, but it must carry high contact stress against both neighbouring rolls.
Induction hardening produces a hard surface layer over a tough, ductile core, which is the ideal combination for an intermediate roll – the surface resists contact fatigue and wear, while the core absorbs bending without fracture. The chromium content of the Cr3 and Cr5 grades controls the hardenability of the induction-hardened layer.
3. Grade Equivalents – Cr3 / Cr5
| Designation | Standard | Notes |
|---|---|---|
| Cr3 type (MC3) | User specification | 3% Cr intermediate roll steel |
| Cr5 type (MC5) | User specification | 5% Cr roll steel |
| 9Cr2Mo | GB/T 1299 | Reference only, not used in certification |
| Grade | C | Si | Mn | Cr | Mo | V |
|---|---|---|---|---|---|---|
| Cr3 type (MC3) | 0.35-0.45 | 0.30-0.60 | 0.50-0.80 | 2.80-3.50 | 0.40-0.70 | – |
| Cr5 type (MC5) | 0.50-0.60 | 0.40-0.70 | 0.50-0.80 | 4.50-5.50 | 0.80-1.20 | 0.10-0.30 |
Composition is agreed to the user specification; the higher chromium and molybdenum of the Cr5 grade give deeper hardenability for larger roll diameters.
4. Manufacturing Process
Melting. FUSHUN METAL melts in an electric arc furnace with ladle refining and, where specified, ESR or vacuum degassing for cleanliness.
Forging. The roll is forged on a 20/80 MN fast forging press with a high reduction ratio, closing porosity and refining the grain.
Hardening. The roll body is induction hardened to the specified surface hardness and depth, leaving a tough core for bending resistance.
Testing. UT, hardness and hardening-depth verification, with full traceability.
5. Standards & Certification
Intermediate rolls are supplied to the user specification, with ultrasonic testing to SEP 1921 and inspection certificates under EN 10204 3.1. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forgings: work rolls and leveller and skin-pass rolls.
6. Typical Applications
Tandem cold mills
Intermediate rolls for multi-stand tandem cold strip mills.
Reversing mills
Intermediate rolls for single-stand reversing mills.
Six-high mills
Intermediate rolls for six-high mill configurations.
Roll blanks
Rough or finish-machined roll blanks to drawing.
7. Inquiry Essentials
To quote your intermediate roll, please provide the body diameter and length, the required surface hardness, the hardening depth, and whether you need a rough blank or a finished roll.
