Penn Stainless inventory now includes Alloy 17-4 (H1025, UNS S17400) in sheet, sheet coil, plate, round bar, processed flat bar and tubular products.
Alloy 17-4 is a chromium-copper precipitation hardening stainless steel that is used for applications requiring high strength and a moderate level of corrosion resistance. It is one of the most widely used precipitation hardening grades, as it has high strength hardness up to about 572°F while demonstrating good corrosion resistance in all heat treated conditions. Alloy 17-4 has adequate resistance to atmospheric corrosion or in diluted acid salts where its corrosion resistance is equivalent to Alloy 304 or 430. Alloy 17-4 can be heat treated to a variety of temperatures to develop a wide range of properties. Its mechanical properties can be optimized with heat treatment where very high yield strength up to 180 ksi can be achieved. Alloy 17-4 should not be used at temperatures above 572°F or at very low temperatures.
Specifications: UNS S17400
Alloy 17-4 is commonly used for applications requiring high strength and a moderate level of corrosion resistance. Some applications that frequently use Alloy 17-4 include:
- Nuclear waste casks
- Paper mills
- Oil fields
- Mechanical components
- Chemical process components
- Food industry
- ASTM/ASME: UNS S17400
- EURONORM: X5CrNiCuNb16.4
- AFNOR: Z6CNU17-04
- DIN: 1.4542
- Withstands corrosive attacks better than any of the standard hardenable stainless steels.
- Comparable to Alloy 304 in most media.
- Corrosion resistant in some chemical, petroleum, dairy, and food process industries.
- Subject to crevice or pitting attack if exposed to stagnant sea water for any length of time.
- Successfully welded by most common fusion and resistance methods.
- Should not be joined by oxyacetylene welding.
- Generally no pre-heating required.
- Inter-pass temperature must be limited to 248°F.
- Better toughness is obtained in the weld after a complete heat treatment.
Elevated Temperature Use:
- Excellent resistance to oxidation to approximately 1100°F.
- Long-term exposure to elevated temperature can result in reduced toughness in the precipitation hardened conditions.
Processing – Hot Forming:
- To forge, heat uniformly to 2150 / 2200°F and hold for half hour per inch.
- Preferred temperature range for hot forming is at 650-900°F, while the steel is still austenitic.
- To ensure the best condition for the hardening operations, the forgings must be re-heat treated at 1875-1925°F.
- Cool forgings to below 90°F to ensure grain refinement.
Processing – Cold Forming:
- Alloy 17-4 is limited to mild operations since in the annealed (solution treated) condition the material is hard.
- For severe cold working the material should be heat treated to condition H1150. This will help prevent possible cracking.
- Bend radius in excess of 7T is often required.
- To improve stress corrosion resistance after cold forming, re-aging at the precipitation-hardening temperature is recommended.
- Can be machined in both solution-treated and precipitation-hardening conditions.
- Machining conditions may vary with hardness of material.
- High-speed tools or preferably carbide tools with standard lubrication are normally used.
|TYPE||Cr||Ni||Cu||Cb + Ta||C||Mn||P||S||Si|
|17-4 (H1025)||min: 15.0
Strength, ksi min.
Strength, ksi min.
|Elongation % in 2″ min.||Reduction in Area
|Heat Treated Condition||H1025|
|Electrical Resistivity, microhm-cm||98|
|Specific Heat, BTU/lb/°F (32-212°F)||0.11|
|Thermal Conductivity, BTU/hr/ft2/in/°F|
|Mean Coefficient of Thermal Expansion, in/in/°F|
|-100 to 70°F||—|
|70 – 200°F||6.0 x 10-6|
|70 – 400°F||6.0 x 10-6|
|70 – 600°F||6.2 x 10-6|
|70 – 800°F||6.3 x 10-6|
|70 – 900°F||—|
|Modulus of Elasticity, ksi||9.68 x 103|
|Modulus of Rigidity, ksi|