440A Stainless Steel Round Bar (UNS S44002)
440A Stainless Steel Round Bar is a high-carbon martensitic stainless steel known for its excellent hardness, wear resistance, and good corrosion resistance among the 440 series. Identified by UNS S44002, this grade offers a balanced combination of strength, edge retention, and corrosion resistance, making it suitable for precision and cutting applications.
Compared to 440B and 440C, 440A provides better corrosion resistance, while still achieving high hardness after heat treatment.
Key Features
- High hardness and wear resistance after heat treatment
- Better corrosion resistance than 440B & 440C
- Excellent polishability and surface finish
- Good edge retention and dimensional stability
- Magnetic in all conditions
- Suitable for precision and cutting tools
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | S44002 |
| AISI | 440A |
| EN | 1.4109 |
| DIN | X70CrMo15 |
| JIS | SUS 440A |
Sizes
- Diameter: 6 mm to 400 mm
- Length: 3 m, 6 m, or cut-to-length
- Tolerance: H8 / H9 / H11 or as required
440A Stainless Steel Chemical Composition
| Element | Percentage (%) |
|---|---|
| Carbon (C) | 0.65 – 0.75 |
| Chromium (Cr) | 16.0 – 18.0 |
| Molybdenum (Mo) | 0.50 – 0.75 |
| Manganese (Mn) | ≤ 1.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
UNS S44002 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 760 – 900 MPa |
| Yield Strength (0.2%) | ≥ 450 MPa |
| Elongation | ≥ 10% |
| Hardness | Up to 56 HRC (depending on heat treatment) |
SS 440A Physical Properties
| Property | Value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting Point | 1480 – 1530°C |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity | 24 W/m·K |
| Electrical Resistivity | 0.60 µΩ·m |
Types of 440A Stainless Steel Round Bar
- Hot Rolled Round Bar
- Cold Drawn Round Bar
- Bright Bar
- Centerless Ground Bar
- Heat-Treated Round Bar
Applications
- Cutlery and knife blades
- Surgical and dental instruments
- Bearings and races
- Valve components
- Precision tools and dies
- High-wear industrial components
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