Description (English)
SUS440C (UNS S44004, DIN 1.4125) high-hardness martensitic stainless steel machined fittings and wear parts for rollers. After quench and temper, 440C reaches 58–60 HRC — the highest hardness of any stainless steel — combined with good corrosion resistance, making it the preferred material for precision roller bearings, guide rollers and cam followers that must run in corrosive or hygienic (food / pharma / marine) environments where 52100 (SUJ2) bearing steel would rust. Vertex Alloy CNC-machines 440C roller races, guide rollers, cam followers, roller shafts, sleeves and retainers per your drawing or sample (reverse engineering from used OEM parts available), to ±0.005 mm with ground raceways Ra 0.2–0.8, sub-zero treatment for dimensional stability, 100% dimensional and hardness inspection, and full heat-number traceability. Every order ships with EN 10204 3.1 certificates, dimensional reports and hardness reports. MOQ from 1 piece; food, beverage, pharmaceutical, marine, textile, printing, aerospace and medical applications supported.
Size Range
- Part Size (max envelope):Up to 300 mm diameter × 400 mm length
- Bar Stock Diameter:3 – 300 mm (ASTM A276)
- Tolerance:Up to ± 0.005 mm (ground)
- Surface Finish:Ra 0.2 – 0.8 (ground raceways)
- Order Quantity:1 piece to series production
Grade Specification
| System | Value |
|---|---|
| UNS (USA) | S44004 |
| AISI (USA) | 440C |
| DIN / EN (Germany/EU) | 1.4125 / X105CrMo17 |
| JIS (Japan) | SUS440C |
| GB (China) | 102Cr17Mo / 9Cr18Mo |
| BS (UK) | 440C / 110CrMo17 |
| AFNOR (France) | Z100CD17 |
Chemical Composition
| Element | Value |
|---|---|
| C | 0.95 – 1.20 |
| Cr | 16.0 – 18.0 |
| Mo | 0.40 – 0.80 |
| Mn | ≤ 1.00 |
| Silicon (Si) | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 1970 MPa (hardened) |
| Yield Strength | ≥ 1900 MPa (hardened) |
| Elongation | ≥ 2 % (hardened) |
| Hardness | 58 – 60 HRC (quench + temper) |
| Impact Energy (annealed) | ≥ 16 J (Charpy V) |
| Hardness (annealed) | ≤ 269 HB (for machining) |
Physical Properties
| Property | Unit | Value |
|---|---|---|
| Density | - | 7.80 g/cm³ |
| Melting Range | - | 1370 – 1400 °C |
| Specific Heat Capacity | - | 460 J/(kg·K) |
| Thermal Conductivity | - | 24.2 W/(m·K) |
| Electrical Resistivity | - | 0.60 μΩ·m |
| Elastic Modulus | - | 200 GPa |
| Thermal Expansion (20–100 °C) | - | 10.2 × 10⁻⁶ /K |
| Magnetic | - | Yes (ferromagnetic) |
Applications
- Bearings
- Food & Beverage
- Pharmaceutical
- Marine
- Textile & Printing
- Aerospace
- Medical / Dental