In industrial fluid systems, valves are the gatekeepers of safety and efficiency. From petrochemical pipelines to hydraulic equipment, valve components require not only high strength but also resistance to wear, corrosion, and deformation under high pressure. The material choice directly determines service life and reliability — and that’s where 630 stainless steel bar (also known as 17-4PH) comes in.
Material Overview: What is 630 Stainless Steel?
630 stainless steel is a precipitation-hardening martensitic stainless steel containing chromium, nickel, and copper. It achieves exceptional mechanical properties through a solution treatment + aging process, resulting in high hardness and tensile strength while maintaining corrosion resistance comparable to 304 stainless steel.
| Property | Description | Value Range |
|---|---|---|
| Chemical Composition | Fe-Cr-Ni-Cu | Cr: 15–17%, Ni: 3–5%, Cu: 3–5% |
| Hardness (HRC) | After aging | 35–44 |
| Tensile Strength (MPa) | Aged condition | ≥1100 |
| Yield Strength (MPa) | Aged condition | ≥1000 |
| Corrosion Resistance | Comparable to 304 | Excellent in air and water environments |
| Processability | Machinable and weldable | Suitable for CNC and precision machining |
Why 630 Stainless Steel is Ideal for Valve Components
Valve bodies, stems, and seat rings are often subjected to alternating pressure and fluid impact. Using ordinary stainless steel bars like 304 or 316 may lead to wear or deformation over time. 630 stainless steel provides a balanced combination of strength and corrosion resistance, making it an excellent solution for high-performance valve parts.
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High tensile and yield strength: resists deformation under hydraulic or steam pressure.
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Excellent corrosion resistance: maintains stability even in seawater or chemical media.
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Good machinability: ideal for precision valve parts produced by CNC lathes.
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Aging treatment stability: ensures consistent hardness and dimensional accuracy.
Typical Applications
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Valve shafts, valve seats, and sealing parts
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Pump shafts and turbine blades
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Hydraulic fittings and coupling components
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Marine valves and chemical flow control systems
These applications all demand materials that won’t fail under load or corrode in contact with aggressive media.
Tongyi Metal’s Quality Advantage
At Tongyi Metal, we provide high-precision 630 stainless steel bars with consistent performance for precision machining. Our bars are stress-relieved and finely ground, ensuring straightness, smoothness, and tight dimensional tolerance.
We control:
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Hardness between HRC 35–40 (adjustable per customer need)
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Straightness deviation ≤0.1mm/m
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Diameter tolerance within ±0.01mm
These standards make our 630 stainless steel bars especially suitable for valve manufacturing, guaranteeing strength, sealing reliability, and longevity in high-demand environments.
When valve components need to perform under high pressure and corrosive environments, material strength and stability are non-negotiable. 630 stainless steel bar combines mechanical robustness with corrosion resistance — the perfect balance for reliable valve performance.
For industrial clients seeking durable materials for critical valve applications, Tongyi Metal offers consistent quality and machining precision that make every component reliable from the inside out.
