17-7PH is a chromium-nickel-aluminum semi-austenitic precipitation-hardening stainless steel offering an exceptional combination of high strength (up to 200 ksi tensile), excellent fatigue life, and good corrosion resistance. Its key advantage lies in its ability to be heat treated with minimal distortion, making it ideal for complex components requiring tight dimensional tolerances. With service capability up to 316°C (600°F), this alloy is widely used for aerospace structural components, springs, bellows, and chemical processing equipment .
1. Product Specifications & Physical DataZYTC Alloy supplies 17-7PH in comprehensive mill forms for aerospace, industrial, and precision engineering applications requiring verified mechanical properties. Available Forms: Sheet, strip, plate, bar (including rounds), tubing, forgings, and welding wire . Specifications: AMS 5528, AMS 5529, AMS 5644, ASTM A693, UNS S17700 .
| Chemical Composition (Weight %) | 17-7PH Specification |
|---|
| Chromium (Cr) | 16.0 - 18.0 | | Nickel (Ni) | 6.50 - 7.75 | | Aluminum (Al) | 0.75 - 1.50 | | Carbon (C) | 0.09 max. | | Manganese (Mn) | 1.0 max. | | Silicon (Si) | 1.0 max. | | Phosphorus (P) | 0.040 max. | | Sulfur (S) | 0.030 max. | | Iron (Fe) | Balance |
| Physical Properties | Metric | Imperial |
|---|
| Density | 7.80 g/cm³ | 0.282 lb/in³ | | Modulus of Elasticity | 204 GPa | 29,600 ksi | | Poisson's Ratio | 0.27 - 0.30 | 0.27 - 0.30 | | Thermal Conductivity (RT) | 16.4 W/m·K | 114 BTU·in/hr·ft²·°F |
| Mechanical Properties | Condition | Metric | Imperial |
|---|
| Tensile Strength (min.) | TH1050 | 1170 MPa | 170 ksi | | Yield Strength (min.) | TH1050 | 965 MPa | 140 ksi | | Elongation | TH1050 | 6% | 6% | | Tensile Strength (min.) | RH950 | 1450 MPa | 210 ksi | | Yield Strength (min.) | RH950 | 1310 MPa | 190 ksi | | Elongation | RH950 | 5% | 5% | | Tensile Strength (min.) | CH900 | 1655 MPa | 240 ksi | | Yield Strength (min.) | CH900 | 1517 MPa | 220 ksi | | Hardness | TH1050 | 38 HRC | 38 HRC | | Hardness | RH950 | 45 HRC | 45 HRC |
2. Fabrication & Material ComparisonHeat Treatment Process (Three-Step): Austenite Conditioning: Solution annealed material heated to specific temperature Martensite Transformation: Cooling to sub-zero temperatures (TH) or hot working/cooling (RH) Precipitation Hardening (Aging): 482-510°C (900-950°F) × 1 hour
Annealing: 1066°C (1950°F) × 3 min per 0.1"thickness, air cool Forming: Good formability in annealed condition; intermediate annealing may be required for severe forming operations . Machining: 75% machinability rating of B1112 steel; produces long, gummy chips requiring chip breakers; slow speeds with constant positive feeds recommended . Welding: Good weldability using TIG, MIG, and resistance methods; inert gas shielding essential to protect aluminum from oxidation . Material Comparison: vs. 17-4PH: Semi-austenitic vs. martensitic; 17-7PH optimized for sheet applications with better formability . vs. 15-7Mo: Lower strength than 15-7Mo RH950; similar forming characteristics . vs. 301 Stainless: Significantly higher strength after heat treatment; better elevated temperature properties .
3. ApplicationsAerospace: Bellows, diaphragms, fasteners, structural components, honeycomb panels Springs: Flat springs, coil springs, spring washers, retaining rings Chemical Processing: Equipment components, vessels, piping Power Generation: Heat exchangers, superheater tubes, power boiler parts General Engineering: High-strength components requiring minimal distortion after heat treatment Instrumentation: Pressure sensor diaphragms, precision components
Contact ZYTC Alloy for certified 17-7PH materials with complete traceability, AMS/ASTM specifications, technical datasheets, and competitive pricing on standard sheet, strip, and bar sizes. Email: daisy@zytcsteel.com WhatsApp/WeChat: +86 17335753350 |
