SS 440C Round Bars Manufacturer – High Carbon Martensitic Stainless Steel
SS 440C is a high-carbon martensitic stainless steel known for its exceptional hardness, high strength, and good corrosion resistance after heat treatment. It belongs to the AISI 440 series (440A, 440B, 440C) and is the hardest and most wear-resistant grade among them.
We are a trusted manufacturer and supplier of SS 440C stainless steel round bars,SS 440C is a high carbon martensitic stainless steel known for its exceptional hardness, wear resistance, and strength after heat treatment.Stainless Steel 440C is a high carbon chromium stainless steel. It has great corrosion resistance when hardened. It shows great resistance to wear and abrasion. It is magnetic in all conditions and yields the highest hardnesses of hardenable stainless steels.
We supply precision-ground and forged 440C round bars that meet international standards and are used across aerospace, tooling, bearing, and mechanical components industries.
SS 440C, also classified under AISI 440C, ASTM A276, or UNS S44004, contains high carbon (typically > 0.95%) and chromium (16–18%), which enable its hardening to a Rockwell hardness of up to 58–60 HRC after proper heat treatment. This makes SS 440C the hardest of all 400-series stainless steels.
Equivalent Grade of A276 Stainless Steel 440C Bars:
| STANDARD | WERKSTOFF NR. | UNS | JIS |
| SS 440C | 1.4125 | S44004 | SUS 440C |
Chemical Composition of SS440C
| UNS Designation⁸ | Type | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Nickel | Molybdenum | Nitrogen | Other Elements¹ | |
| S44004 | 440C | 0.95 – 1.20 | 1 | 0.04 | 0.03 | 1 | 16.0 – 18.0 | … | 0.75 | … | … |
SS 440C Round Bar Specifications
| Property | Description |
|---|---|
| Grade | SS 440C / AISI 440C / UNS S44004 |
| Standard | ASTM A276 / AISI / EN / DIN |
| Diameter Range | 8 mm to 300 mm |
| Length | 1000 mm – 6000 mm (custom cut available) |
| Surface Finish | Peeled, polished, ground, rough-turned |
| Condition | Annealed (A), Hardened & Tempered (H&T), QT |
| Hardness | Up to 58–60 HRC after heat treatment |
SS 440C Round Bar Mechanical Property
| grade | shape | size range | tensile ksi | yield ksi | elongation % | Red. of area % | brinell hardness | relative machinability* | specification |
| 440C | Rounds | 1/4″ – 8″ | 110 | 65 | 14 | 25 | 230 | 40% | AMS 5630 / ASTM A-276 |
| 440C BQ | Rounds | 1/2″ – 6″ | – | – | – | – | – | – | AMS 5630/5880 / ASTM A-276/ A-756 |
Standards for 440C round bars
- ASTM A276 – Stainless Steel Bars and Shapes
- ASTM A484 – General Requirements for SS Bars
- UNS S44004
- DIN 1.4125 / X105CrMo17
- EN 10088-3
AISI 440C Round Bar Packaging & Certification
- Export-grade packaging (wooden crates, bundles)
- Marking: Grade, Heat Number, Size, Condition
- MTC EN 10204 3.1 provided
Heat Treatment of 440C Round Bar
- Hardening: Heat to 1010°C–1065°C (1850°F–1950°F) and quench in oil or air
- Tempering: Temper at 150°C–370°C (302°F–698°F) to achieve desirable combination of toughness and hardness
- Soft Annealing (optional): Heat to 780°C–820°C (1436°F–1508°F) and slowly cool to ease machinability
Order Example:
Material: 440C Stainless Steel Round Bar
Standard: ASTM A276
Condition: Hardened & Tempered
Size: Ø50 mm × 6000 mm
Quantity: 2 Tons
Finish: Bright polished
As a leading SS 440C round bar manufacturer and supplier, we specialize in producing high-quality AISI 440C stainless steel bars that deliver exceptional hardness, wear resistance, and mechanical strength. Manufactured to strict international standards such as ASTM A276, ASTM A479, and AMS 5630, our 440C round bars are ideal for critical engineering and industrial applications.
