17-4PH Stainless Steel Round Bar
Grade: 630/17-4PH/UNS S17400
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
630 stainless steel, commonly known as 17-4PH stainless steel, is a precipitation-hardening martensitic stainless steel grade designated as UNS S17400. It is one of the most widely used precipitation-hardening stainless steels due to its excellent combination of high strength, hardness, corrosion resistance, and toughness. The designation “17-4PH” refers to its approximate alloy composition of 17% chromium and 4% nickel, with copper and niobium additions that enable precipitation hardening.
Unlike conventional martensitic stainless steels, 17-4PH stainless steel achieves high mechanical properties through a precipitation-hardening heat treatment process rather than only through carbon-based hardening. The addition of copper allows the formation of fine copper-rich precipitates during aging treatment, significantly increasing strength and hardness while maintaining good corrosion resistance. Niobium stabilizes carbon and improves structural stability.
630 stainless steel bars are typically supplied in solution-treated condition (Condition A) and can be aged to various conditions such as H900, H1025, H1150, and H1150M depending on the required balance between strength, toughness, and corrosion resistance. The material provides excellent dimensional stability during heat treatment, making it suitable for precision components.
Due to its high strength-to-weight ratio, good corrosion resistance, and excellent fatigue performance, 17-4PH stainless steel bars are widely used in aerospace components, oil and gas equipment, chemical processing systems, marine applications, valve components, pump shafts, fasteners, and high-performance mechanical parts. It is particularly suitable for applications requiring high mechanical strength combined with corrosion resistance.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A564 / A564M – UNS S17400 | Wrought Precipitation-Hardening Stainless Steel Bars |
| ASTM | ASTM A705 / A705M – UNS S17400 | Age-Hardening Stainless Steel Forgings |
| ASTM | ASTM A276 / A276M – UNS S17400 | Stainless Steel Bars and Shapes |
| UNS | S17400 | 17-4PH Stainless Steel Grade |
| JIS | JIS G4303 SUS630 | Stainless Steel Bars |
| EN | EN 10088-3 1.4542 | X5CrNiCuNb16-4 Stainless Steel |
| DIN | DIN 1.4542 | 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 | Solution Treatment + Aging Treatment |
| Solution Treatment | Approximately 1040°C followed by rapid cooling |
| Aging Conditions | H900 / H1025 / H1150 / H1150M |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A564 / ASTM A276 |
| Inspection | Chemical Analysis, Mechanical Testing, Hardness Testing, Dimensional Inspection |
| Supply Condition | Solution Treated, Age Hardened, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | ≤ 0.07 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 15.00 – 17.50 |
| Nickel (Ni) | 3.00 – 5.00 |
| Copper (Cu) | 3.00 – 5.00 |
| Niobium + Tantalum (Nb+Ta) | 0.15 – 0.45 |
| Iron (Fe) | Balance |
Mechanical Properties
Typical Aging Conditions
| Property | H900 Condition | H1150 Condition |
| Tensile Strength | ≥ 1310 MPa | ≥ 930 MPa |
| Yield Strength (0.2% Offset) | ≥ 1170 MPa | ≥ 690 MPa |
| Elongation | ≥ 10% | ≥ 16% |
| Hardness | Approx. 40–44 HRC | Approx. 28–32 HRC |
| Condition | Age Hardened | Age Hardened |
| Industry | Applications |
| Aerospace Industry | Aircraft structural components, landing gear parts, shafts |
| Oil & Gas Industry | Valves, pump components, high-pressure equipment |
| Marine Industry | Marine shafts, fasteners, corrosion-resistant structures |
| Chemical Industry | Reactor components, processing equipment |
| Power Generation | Turbine components, high-strength fasteners |
| Mechanical Engineering | Gears, shafts, precision components |
| Mold Industry | High-strength molds and tooling components |
630 stainless steel, commonly known as 17-4PH stainless steel, is a precipitation-hardening martensitic stainless steel grade designated as UNS S17400. It is one of the most widely used precipitation-hardening stainless steels due to its excellent combination of high strength, hardness, corrosion resistance, and toughness. The designation “17-4PH” refers to its approximate alloy composition of 17% chromium and 4% nickel, with copper and niobium additions that enable precipitation hardening.
Unlike conventional martensitic stainless steels, 17-4PH stainless steel achieves high mechanical properties through a precipitation-hardening heat treatment process rather than only through carbon-based hardening. The addition of copper allows the formation of fine copper-rich precipitates during aging treatment, significantly increasing strength and hardness while maintaining good corrosion resistance. Niobium stabilizes carbon and improves structural stability.
630 stainless steel bars are typically supplied in solution-treated condition (Condition A) and can be aged to various conditions such as H900, H1025, H1150, and H1150M depending on the required balance between strength, toughness, and corrosion resistance. The material provides excellent dimensional stability during heat treatment, making it suitable for precision components.
Due to its high strength-to-weight ratio, good corrosion resistance, and excellent fatigue performance, 17-4PH stainless steel bars are widely used in aerospace components, oil and gas equipment, chemical processing systems, marine applications, valve components, pump shafts, fasteners, and high-performance mechanical parts. It is particularly suitable for applications requiring high mechanical strength combined with corrosion resistance.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A564 / A564M – UNS S17400 | Wrought Precipitation-Hardening Stainless Steel Bars |
| ASTM | ASTM A705 / A705M – UNS S17400 | Age-Hardening Stainless Steel Forgings |
| ASTM | ASTM A276 / A276M – UNS S17400 | Stainless Steel Bars and Shapes |
| UNS | S17400 | 17-4PH Stainless Steel Grade |
| JIS | JIS G4303 SUS630 | Stainless Steel Bars |
| EN | EN 10088-3 1.4542 | X5CrNiCuNb16-4 Stainless Steel |
| DIN | DIN 1.4542 | 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 | Solution Treatment + Aging Treatment |
| Solution Treatment | Approximately 1040°C followed by rapid cooling |
| Aging Conditions | H900 / H1025 / H1150 / H1150M |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A564 / ASTM A276 |
| Inspection | Chemical Analysis, Mechanical Testing, Hardness Testing, Dimensional Inspection |
| Supply Condition | Solution Treated, Age Hardened, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | ≤ 0.07 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 15.00 – 17.50 |
| Nickel (Ni) | 3.00 – 5.00 |
| Copper (Cu) | 3.00 – 5.00 |
| Niobium + Tantalum (Nb+Ta) | 0.15 – 0.45 |
| Iron (Fe) | Balance |
Mechanical Properties
Typical Aging Conditions
| Property | H900 Condition | H1150 Condition |
| Tensile Strength | ≥ 1310 MPa | ≥ 930 MPa |
| Yield Strength (0.2% Offset) | ≥ 1170 MPa | ≥ 690 MPa |
| Elongation | ≥ 10% | ≥ 16% |
| Hardness | Approx. 40–44 HRC | Approx. 28–32 HRC |
| Condition | Age Hardened | Age Hardened |
| Industry | Applications |
| Aerospace Industry | Aircraft structural components, landing gear parts, shafts |
| Oil & Gas Industry | Valves, pump components, high-pressure equipment |
| Marine Industry | Marine shafts, fasteners, corrosion-resistant structures |
| Chemical Industry | Reactor components, processing equipment |
| Power Generation | Turbine components, high-strength fasteners |
| Mechanical Engineering | Gears, shafts, precision components |
| Mold Industry | High-strength molds and tooling components |
