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.
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.
High tensile and yield strength
Excellent corrosion resistance, even in chloride-containing environments
Good machinability and weldability
Can be heat-treated to various conditions (H900, H1025, H1150, etc.)
| 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 |
| 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.)
One of the advantages of 17-4PH stainless steel is the flexibility in mechanical properties through different heat treatment conditions:
Condition A (Solution Annealed): Softest condition, ideal for machining and forming
H900: Maximum hardness and strength
H1025: Balanced strength and ductility
H1150 & H1150-D: Enhanced toughness and corrosion resistance
Thanks to its combination of strength and corrosion resistance, 17-4PH round bar is widely used in the following sectors:
Aerospace: Structural components, shafts, fasteners
Oil & Gas: Valve components, gears, pump shafts
Marine Industry: Propeller shafts, fittings, bolts
Nuclear Waste Handling: Corrosion-resistant containment structures
Tool & Die Making: Injection molds, precision parts
| Standard | Designation |
|---|---|
| ASTM | A564 Type 630 |
| UNS | S17400 |
| EN | 1.4542 / X5CrNiCuNb16-4 |
| AISI | 630 |
| AMS | AMS 5643 |
| JIS | SUS630 |
SAKY STEEL is a leading manufacturer and global exporter of 17-4PH round bars, with a reputation for quality, reliability, and precision.
✅ 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: Wooden crates, waterproof wrapping, and barcode labeling
Delivery Time: 7–15 days depending on quantity
Export Markets: Europe, Middle East, Southeast Asia, North America