AISI 440C / UNS S44004 (Martensitic) Stainless Steel
Chemistry, mechanical properties, physical properties, and practical selection notes for rolled AISI 440C products.
Performance & Use Notes
- High-carbon martensitic stainless capable of very high hardness for wear/bearing/blade applications.
- Corrosion resistance depends heavily on heat treatment and surface condition.
Standards & Designations
Data Tables
- High-carbon, high-hardness martensitic stainless; used for bearings, valves, and high-end blades.
| Chemical composition (wt%) | Specification limits (Atlas) |
|---|---|
| C | 0.95–1.20 |
| Mn | 1.00 max |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 16.00–18.00 |
| Mo | 0.75 max |
| Mechanical (typical / specified values) | Atlas 440C |
|---|---|
| Annealed | UTS 758 MPa; YS 448 MPa; Elong 14%; Hardness 269 HB max |
| Tempered 204°C | UTS 2030 MPa; YS 1900 MPa; Elong 4%; 59 HRC |
| Tempered 316°C | UTS 1860 MPa; YS 1740 MPa; Elong 4%; 56 HRC |
Values shown are typical/spec limits at room temperature unless noted; requirements vary by product form, size, and specification.
440C stainless steel from Source21 is a high carbon martensitic stainless steel grade engineered for maximum hardness wear resistance and dimensional stability. Known as one of the hardest stainless steels available Type 440C can be heat treated to reach Rockwell C60 making it ideal for applications requiring extreme durability and long service life. It offers good corrosion resistance for a high hardness alloy while maintaining precision and stability under demanding conditions. Common uses include bearings surgical blades dies valve seats and high precision tools where performance and accuracy are critical.
Source21 supplies 440C stainless steel in coil, strip, sheet, foil, and bar, all manufactured to meet ASTM A276 and AMS 5630 standards.
Contact the Source21 team to place an order review available forms or receive expert guidance for high hardness stainless steel applications supported by reliable supply and responsive service.