AMS 6302 is an SAE International aerospace material specification covering aircraft‑quality, low‑alloy, heat‑resistant steel in the form of bars, forgings, mechanical tubing, and forging stock. The alloy designated under this specification is UNS K23015, commercially known as 17‑22A (or 17‑22A(S)).
17‑22A is a structural low‑alloy ultra‑high‑strength steel offering excellent high‑temperature strength, outstanding heat resistance, and good oxidation resistance at elevated temperatures. With significant additions of carbon, molybdenum, vanadium, and chromium, this alloy achieves its high strength through precipitation hardening and is widely used in the manufacture of shafts and fasteners.
The 17‑22A alloy steel responds quickly to heat treatment and offers good machinability and toughness, performing particularly well under short‑time high‑temperature exposure. It is typically used for components exposed to high temperatures for relatively short durations, making it a critical structural material in aerospace engines, missile systems, and industrial turbine machinery.
Specifications and Standards
17‑22A / UNS K23015 alloy steel conforms to the following major international standards:
| Standard | Description | Product Form |
|---|
| AMS 6302 | Low‑Alloy Heat‑Resistant Steel Bars, Forgings, and Tubing (primary aerospace standard) | Bar, forging, tube |
| AMS 6385 | Low‑Alloy Heat‑Resistant Steel Plate, Strip, and Sheet | Plate, strip, sheet |
| AMS 6458 | Vacuum‑Melted Welding Wire | Wire |
| AMS 6303 | Low‑Alloy Heat‑Resistant Steel Bars and Forgings (V‑type) | Bar, forging |
| AMS 6304 | Low‑Alloy Heat‑Resistant Steel Bars, Forgings, and Tubing | Bar, forging, tube |
| AMS 6305 | Low‑Alloy Heat‑Resistant Steel Bars and Forgings | Bar, forging |
| UNS K23015 | Unified Numbering System | Material designation |
Chemical Composition
The chemical composition of 17‑22A alloy steel is precisely engineered to achieve precipitation hardening and high‑temperature strength through chromium, molybdenum, and vanadium additions. The composition requirements (based on AMS 6302 / UNS K23015) are as follows:
| Element | Weight % (min) | Weight % (max) | Function |
|---|
| Carbon (C) | 0.28 | 0.33 | Provides strength and hardenability |
| Silicon (Si) | 0.55 | 0.75 | Improves heat resistance and oxidation resistance |
| Manganese (Mn) | – | 0.55 | Deoxidiser |
| Chromium (Cr) | 1.00 | 1.50 | Enhances corrosion resistance and high‑temperature strength |
| Molybdenum (Mo) | 0.40 | 0.60 | Increases high‑temperature strength and resistance to temper softening |
| Vanadium (V) | 0.20 | 0.30 | Refines grain size, improves high‑temperature strength |
| Nickel (Ni) | – | – | Tightly controlled |
| Phosphorus (P) | – | ≤ 0.025 | Tightly controlled |
| Sulfur (S) | – | ≤ 0.025 | Tightly controlled |
| Iron (Fe) | Balance | Balance | Matrix |
Key characteristics: 17‑22A is classified as a low‑alloy heat‑resistant steel with a typical composition of 0.65Si – 1.25Cr – 0.50Mo – 0.25V (carbon 0.28–0.33C). The synergistic effect of chromium, molybdenum, and vanadium imparts excellent high‑temperature strength and creep resistance to the alloy.
Mechanical Properties
The mechanical properties of 17‑22A alloy steel depend on the heat treatment condition. Typical property data after appropriate heat treatment are summarised below:
| Property | Value | Unit | Remarks |
|---|
| Yield Strength (Rp0.2) | ≥ 926 | MPa | After solution + aging |
| Tensile Strength (Rm) | ≥ 891 | MPa | After solution + aging |
| Impact Energy | ≥ 33 | J | After solution + aging |
| Elongation (A) | ≥ 24 | % | After solution + aging |
| Reduction of Area (Z) | ≥ 32 | % | After solution + aging |
| Brinell Hardness | ≤ 244 | HBW | After solution + aging |
Key performance interpretation:
Ultra‑high strength: Yield strength exceeds 926 MPa, tensile strength exceeds 891 MPa – placing this material in the ultra‑high‑strength steel category.
Excellent toughness: Impact energy ≥ 33 J, elongation ≥ 24%, ensuring safety under impact loading.
High‑temperature rupture strength: At 1100°F (593°C), the 1000‑hour rupture strength is approximately 30,000 psi (about 207 MPa). At 1200°F, the 100‑hour rupture strength is about 28,000–30,000 psi.
Notch sensitivity: In rupture tests exceeding 100 hours, the material shows some notch sensitivity, which can be mitigated through proper component design.
Physical Properties
| Property | Value | Unit |
|---|
| Density | ~7.85 | g/cm³ |
| Elastic Modulus | ~200 | GPa |
Product Forms and DimensionsZYTC Alloy supplies 17‑22A / UNS K23015 alloy steel in the following product forms: | Product Form | Dimensional Range |
|---|
| Round Bar / Bar Stock | Diameter 6.0 to 750 mm | | Square / Flat Bar | 10 to 400 mm | | Forgings | Stepped shafts and other custom shapes | | Tubing | Custom per customer requirements | | Length | Fixed or random lengths, or custom per customer specification |
ZYTC Alloy can also provide ultrasonic testing (UT) services according to various standard grades to meet specific buyer requirements. |  |
Applications
17‑22A alloy steel, with its unique combination of ultra‑high strength, excellent high‑temperature performance, and good toughness, is widely used in the following fields:
| Industry | Typical Applications |
|---|
| Aerospace | Engine mechanical components, missile parts, turbine rotors, aircraft structural parts |
| Aerospace Fasteners | Studs, bolts, fasteners |
| Power Generation & Turbines | Steam turbines, industrial furnaces |
| Petrochemical | Petrochemical equipment, high‑temperature piping |
| General Machinery | Shaft components, mechanical parts under high‑temperature conditions |
Core application scenarios:
Shaft components: Drive shafts, turbine shafts, and other rotating parts subjected to high temperatures and high stresses
Fasteners: Studs, bolts, and fasteners for high‑temperature service
Engine components: Critical structural parts for aircraft engines and industrial gas turbines
Missile systems: High‑temperature structural components for guided missiles
Industrial furnaces: Heat‑resistant furnace components
ZYTC Alloy – A Professional Chinese Supplier of Special Alloys
Tianjin ZYTC Alloy Technology Co., Ltd. (ZYTC Alloy) is a comprehensive supply chain management company with over 30 years of management experience in the steel industry. Headquartered in Tianjin, China, ZYTC integrates the melting, forging, rolling, heat treatment, processing services, inspection, and logistics distribution of special alloys.
ZYTC Alloy offers the following core strengths in high‑end alloy steels:
| Capability | Details |
|---|
| Standards covered | AMS 6302, AMS 6385, AMS 6303, AMS 6304, UNS K23015 |
| Product forms | Round bar, square bar, flat bar, forgings, tubing, wire |
| Quality system | Provides mill test reports certified by authorities such as TUV, SGS, BV |
| Industry experience | Over 30 years in specialty metals management |
| Global reach | Products exported to many countries and regions worldwide |
| Technical support | In‑house metallurgical engineering team for application consultation |
ZYTC Alloy deeply understands the special nature of aircraft‑quality low‑alloy heat‑resistant steels like AMS 6302 17‑22A – customers are not just buying material, but also “performance consistency” and “completeness of technical documentation.” Each batch is supplied with a full mill test report (including chemical composition and mechanical property test data), ensuring full compliance with AMS 6302 requirements.
ZYTC Alloy is committed to providing certified, traceable, precision‑engineered special alloys for the aerospace, power generation, and petrochemical industries. For AMS 6302 17‑22A alloy steel bar requirements, ZYTC Alloy offers customised services per customer specifications, including precision machining, cutting, and heat treatment value‑added services.
Contact ZYTC Alloy to obtain official AMS 6302 17-22A datasheets, batch inspection reports and competitive bulk quotations.
📧 Email: daisy@zytcsteel.com
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