440A Stainless Steel Round Bar
Grade: 440A/UNS S44002
Size:
Cold drawn: φ4mm-φ60mm
Hot Rolled: φ16mm-φ230mm
Forged: φ230mm-φ1200mm
Surface Finish: Black Annealed, Polished Bright, Centerless Grinding
Diameter Tolerance: H9, H11, h9, h11 etc
- Fast Shipping / Ready Stock
- ISO 9001 Direct Factory
- Custom Cutting & Processing
- 100% MTC & SGS Inspection Supported
440A stainless steel is a high-carbon martensitic chromium stainless steel grade designated as UNS S44002. It is specifically developed for applications requiring high hardness, excellent wear resistance, good edge retention, and moderate corrosion resistance. Among the 440 series stainless steels, 440A contains a slightly lower carbon content than 440B and 440C, providing a better balance of toughness, corrosion resistance, and hardness while maintaining excellent wear performance.
The alloy contains chromium as the primary alloying element and a relatively high carbon content that allows the formation of a hard martensitic structure after heat treatment. Chromium provides corrosion resistance through the formation of a passive chromium oxide film, while carbon contributes to the formation of chromium carbides that significantly improve hardness and abrasion resistance. The microstructure after hardening consists of tempered martensite with carbide particles, providing excellent mechanical durability.
440A stainless steel bars are typically supplied in annealed condition for machining and can be hardened through quenching and tempering processes. After heat treatment, the material can achieve high hardness levels while maintaining better toughness and corrosion resistance than higher-carbon 440B and 440C grades. It offers good polishing characteristics and can achieve a smooth surface finish suitable for precision applications.
Due to its combination of hardness, wear resistance, and corrosion resistance, 440A stainless steel bars are widely used in cutlery, surgical instruments, bearings, valves, molds, precision tools, and mechanical wear components. It is particularly suitable for applications where high hardness and corrosion resistance are required but extreme cutting performance is not the primary requirement.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A276 / A276M – UNS S44002 | Stainless Steel Bars and Shapes |
| ASTM | ASTM A580 / A580M – UNS S44002 | Stainless Steel Wire and Bar Products |
| UNS | S44002 | 440A Stainless Steel Grade |
| JIS | JIS G4303 SUS440A | Stainless Steel Bars |
| EN | EN 10088-3 1.4109 | X70CrMo15 Stainless Steel (Comparable Grade) |
| DIN | DIN 1.4109 | Equivalent European Material Designation |
Stainless Steel Bar Execution Standards
| Item | Specification |
| Product Type | Round Bar, Square Bar, Hexagonal Bar |
| Manufacturing Process | Hot Rolled, Cold Drawn, Peeled, Ground, Polished |
| Heat Treatment | Annealed, Hardened and Tempered |
| Annealing Temperature | Approximately 815–900°C |
| Hardening Temperature | Approximately 1010–1065°C followed by oil or air cooling |
| Tempering Temperature | Approximately 150–370°C depending on hardness requirements |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A276 / customer requirements |
| Inspection | Chemical Analysis, Hardness Testing, Mechanical Testing, Dimensional Inspection |
| Supply Condition | Annealed, Heat Treated, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | 0.60 – 0.75 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 16.00 – 18.00 |
| Molybdenum (Mo) | ≤ 0.75 |
| Nickel (Ni) | ≤ 0.60 |
| Iron (Fe) | Balance |
Mechanical Properties
Hardened and Tempered Condition (Typical)
| Property | Requirement |
| Tensile Strength | 760–950 MPa |
| Yield Strength (0.2% Offset) | ≥ 450 MPa |
| Elongation | ≥ 10% |
| Hardness | 54–58 HRC (Typical) |
| Condition | Hardened and Tempered |
Annealed Condition (Typical)
| Property | Requirement |
| Tensile Strength | Approximately 760 MPa |
| Hardness | ≤ 269 HB |
| Condition | Annealed |
| Industry | Applications |
| Cutlery Industry | Knives, blades, scissors, cutting tools |
| Medical Industry | Surgical instruments, dental tools |
| Bearing Industry | Small bearings, wear-resistant components |
| Mold Industry | Plastic molds, precision tooling |
| Valve Industry | Valve seats, sealing components |
| Mechanical Engineering | Wear plates, bushings, precision parts |
| Food Processing | Cutting blades and processing equipment |
440A stainless steel is a high-carbon martensitic chromium stainless steel grade designated as UNS S44002. It is specifically developed for applications requiring high hardness, excellent wear resistance, good edge retention, and moderate corrosion resistance. Among the 440 series stainless steels, 440A contains a slightly lower carbon content than 440B and 440C, providing a better balance of toughness, corrosion resistance, and hardness while maintaining excellent wear performance.
The alloy contains chromium as the primary alloying element and a relatively high carbon content that allows the formation of a hard martensitic structure after heat treatment. Chromium provides corrosion resistance through the formation of a passive chromium oxide film, while carbon contributes to the formation of chromium carbides that significantly improve hardness and abrasion resistance. The microstructure after hardening consists of tempered martensite with carbide particles, providing excellent mechanical durability.
440A stainless steel bars are typically supplied in annealed condition for machining and can be hardened through quenching and tempering processes. After heat treatment, the material can achieve high hardness levels while maintaining better toughness and corrosion resistance than higher-carbon 440B and 440C grades. It offers good polishing characteristics and can achieve a smooth surface finish suitable for precision applications.
Due to its combination of hardness, wear resistance, and corrosion resistance, 440A stainless steel bars are widely used in cutlery, surgical instruments, bearings, valves, molds, precision tools, and mechanical wear components. It is particularly suitable for applications where high hardness and corrosion resistance are required but extreme cutting performance is not the primary requirement.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A276 / A276M – UNS S44002 | Stainless Steel Bars and Shapes |
| ASTM | ASTM A580 / A580M – UNS S44002 | Stainless Steel Wire and Bar Products |
| UNS | S44002 | 440A Stainless Steel Grade |
| JIS | JIS G4303 SUS440A | Stainless Steel Bars |
| EN | EN 10088-3 1.4109 | X70CrMo15 Stainless Steel (Comparable Grade) |
| DIN | DIN 1.4109 | Equivalent European Material Designation |
Stainless Steel Bar Execution Standards
| Item | Specification |
| Product Type | Round Bar, Square Bar, Hexagonal Bar |
| Manufacturing Process | Hot Rolled, Cold Drawn, Peeled, Ground, Polished |
| Heat Treatment | Annealed, Hardened and Tempered |
| Annealing Temperature | Approximately 815–900°C |
| Hardening Temperature | Approximately 1010–1065°C followed by oil or air cooling |
| Tempering Temperature | Approximately 150–370°C depending on hardness requirements |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A276 / customer requirements |
| Inspection | Chemical Analysis, Hardness Testing, Mechanical Testing, Dimensional Inspection |
| Supply Condition | Annealed, Heat Treated, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | 0.60 – 0.75 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 16.00 – 18.00 |
| Molybdenum (Mo) | ≤ 0.75 |
| Nickel (Ni) | ≤ 0.60 |
| Iron (Fe) | Balance |
Mechanical Properties
Hardened and Tempered Condition (Typical)
| Property | Requirement |
| Tensile Strength | 760–950 MPa |
| Yield Strength (0.2% Offset) | ≥ 450 MPa |
| Elongation | ≥ 10% |
| Hardness | 54–58 HRC (Typical) |
| Condition | Hardened and Tempered |
Annealed Condition (Typical)
| Property | Requirement |
| Tensile Strength | Approximately 760 MPa |
| Hardness | ≤ 269 HB |
| Condition | Annealed |
| Industry | Applications |
| Cutlery Industry | Knives, blades, scissors, cutting tools |
| Medical Industry | Surgical instruments, dental tools |
| Bearing Industry | Small bearings, wear-resistant components |
| Mold Industry | Plastic molds, precision tooling |
| Valve Industry | Valve seats, sealing components |
| Mechanical Engineering | Wear plates, bushings, precision parts |
| Food Processing | Cutting blades and processing equipment |
