17-4PH steel is the most widely used of the precipitation hardenable stainless steels due to its combination of high mechanical strength, good corrosion resistance, and excellent mechanical properties up to 316°C.
This martensitic alloy offers engineers the ability to improve product reliability by simplifying manufacturing processes and often reducing costs. It is ideal for applications in corrosive environments that require high strength and hardness.

Reference standards:

• UNS S17400
• W. Nr. 1.4542
• AMS 5604
• ASTM A693, ASTM F899
• ASME SA693
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Chemical composition (%)

Element Content (%)
Chromium (Cr) 15.0 – 17.5
Nickel (Ni) 3.0 – 5.0
Copper (Cu) 3.0 – 5.0
Manganese (Mn) ≤1.00
Silicon (Si) ≤1.00
Carbon (C) ≤0.07
Phosphorus (P) ≤0.04
Sulfur (S) ≤0.03
Columbium + Tantalum (Cb+Ta) 0.15 – 0.45
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Mechanical properties (typical for cold annealed sheet and strip)

Property Value
Tensile Strength (UTS) 1103 MPa (160 ksi)
Yield Strength 0.2% 1000 MPa (145 ksi)
Elongation at 50mm 5%
Hardness (Rockwell C) 35 HRC
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Physical properties

Property Value
Density 0.2820 lb/in³
Melting range 1404 – 1440°C
Electrical resistivity 98 µΩ cm
Thermal expansion (21–316°C) 11.2 µm/m°C
Thermal conductivity 17.9 – 22.6 W/mK (at 149–482°C)
Specific heat (0-100°C) 460 J/kgK
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Heat treatments

• Solution annealing: Annealing between 1040-1065°C followed by quenching in air or oil.
• Aging: Standard conditions H900, H1025, H1075, H1150 to optimize strength, ductility and toughness.
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Available formats

• Sheets and strips: thickness 0.032″ – 0.1425″
• Plates: thickness 0.1875″ – 2.500″
• Bars: diameter 0.250″ – 5.000″
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Industrial applications

Thanks to its excellent corrosion resistance and high mechanical performance, 17-4PH is used in the following sectors:
• Aerospace and Defense: Structural and support components.
• Power Generation: Turbines, pumps and valves.
• Chemical and Petrochemical Industry: Treatment plants, reactors and valves.
• Food Processing: Food-grade stainless steel equipment.
• Motorsport: High-strength, lightweight structural screws and parts.
• Nuclear: Structural components for reactors.