Introduction
The demand for high-strength, corrosion-resistant materials in the aerospace, marine, and chemical industries has led to the growing popularity of ASTM A564 Type 630 stainless steel round bar, commonly known as 17-4PH or UNS S17400. This precipitation-hardening martensitic stainless steel provides an excellent balance of strength, toughness, and corrosion resistance.
In this article, SAKY STEEL introduces the key features, technical specifications, applications, and supply capabilities of 17-4PH round bars, offering insight for engineers, buyers, and manufacturers across industries.
What is ASTM A564 Type 630 / 17-4PH Stainless Steel?
ASTM A564 Type 630 is the standard specification for hot- and cold-finished age-hardened stainless steel bars and shapes, commonly referred to as 17-4 precipitation hardening stainless steel. This alloy is composed of chromium, nickel, and copper, with added niobium to enhance strength through precipitation hardening.
Key Properties:
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High tensile and yield strength
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Excellent corrosion resistance, even in chloride-containing environments
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Good machinability and weldability
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Can be heat-treated to various conditions (H900, H1025, H1150, etc.)
Chemical Composition (%):
| Element | Content Range |
|---|---|
| Chromium (Cr) | 15.0 – 17.5 |
| Nickel (Ni) | 3.0 – 5.0 |
| Copper (Cu) | 3.0 – 5.0 |
| Niobium + Tantalum | 0.15 – 0.45 |
| Carbon (C) | ≤ 0.07 |
| Manganese (Mn) | ≤ 1.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
Mechanical Properties (Typical at H900 Condition):
| Property | Value |
|---|---|
| Tensile Strength | ≥ 1310 MPa |
| Yield Strength (0.2%) | ≥ 1170 MPa |
| Elongation | ≥ 10% |
| Hardness | 38 – 44 HRC |
Note: Properties vary with heat treatment condition (H900, H1025, H1150, etc.)
Heat Treatment Conditions Explained
One of the advantages of 17-4PH stainless steel is the flexibility in mechanical properties through different heat treatment conditions:
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Condition A (Solution Annealed): Softest condition, ideal for machining and forming
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H900: Maximum hardness and strength
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H1025: Balanced strength and ductility
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H1150 & H1150-D: Enhanced toughness and corrosion resistance
Applications of 17-4PH Round Bars
Thanks to its combination of strength and corrosion resistance, 17-4PH round bar is widely used in the following sectors:
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Aerospace: Structural components, shafts, fasteners
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Oil & Gas: Valve components, gears, pump shafts
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Marine Industry: Propeller shafts, fittings, bolts
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Nuclear Waste Handling: Corrosion-resistant containment structures
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Tool & Die Making: Injection molds, precision parts
Standards and Designations
| Standard | Designation |
|---|---|
| ASTM | A564 Type 630 |
| UNS | S17400 |
| EN | 1.4542 / X5CrNiCuNb16-4 |
| AISI | 630 |
| AMS | AMS 5643 |
| JIS | SUS630 |
Why Choose SAKY STEEL for 17-4PH Round Bars?
SAKY STEEL is a leading manufacturer and global exporter of 17-4PH round bars, with a reputation for quality, reliability, and precision.
Our Advantages:
✅ ISO 9001:2015 certified
✅ Extensive stock in all heat treatment conditions
✅ Diameter range from 6mm to 300mm
✅ Custom cutting, export packaging, fast delivery
✅ In-house ultrasonic testing, PMI, and mechanical test lab
Packaging & Shipping
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Packaging: Wooden crates, waterproof wrapping, and barcode labeling
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Delivery Time: 7–15 days depending on quantity
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Export Markets: Europe, Middle East, Southeast Asia, North America
Post time: Jul-07-2025