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 17-4PH, UNS S17400, W.Nr. 1.4542


17-4PH is a chromium-nickel-copper precipitation-hardening martensitic stainless steel with an addition of niobium, combines high strength and hardness with good corrosion resistance. The material is magnetic and excellent mechanical characteristics, can be easily welded and processed by standard shop fabrication practices. Also, 17-4PH stainless steel provides high resistance to crack propagation, good transverse properties, and proven resistance to stress corrosion cracking in marine environments. 

  • Aerospace Industry: Structural components, landing gear, and aircraft fittings
  • Oil and Gas Industry: Valve components, wellhead equipment, and downhole tools
  • Chemical Processing: Pumps, valves, and heat exchangers
  • Medical Applications: Surgical instruments, orthopedic implants, and dental tools
  • Defense Applications: Barrels, firing pins, and receivers
Chemical Composition (%)
Material Cr Ni Cu C Mn P S Si
17-4PH 15.0-17.5 3.00-5.00 3.00-5.00 0.07 max 1.00 max 0.04 max 0.03 max 1.00 max
Mechanical Property
Material Tensile strength Yield strength 0,2 Elongation Hardness HB30
17-4PH 1105 N/mm² 1000 N/mm² 15% 363HB
Corrosion Resistance

17-4PH has good  corrosive resistance, is comparable to 304 stainless steel in most environments, and is generally superior to the 400 series stainless steels. Its suitable for applications where the combination of moderate corrosion resistance and unusually high strength are required. Like 304, this grade is subject to pitting and crevice corrosion in warm chloride environments. Highly resistant to stress corrosion cracking if aged at 550°C or higher. Higher aging temperatures give better SCC resistance. Its important to note that 17-4PH material should not generally be put in service in the solution-annealed condition A, because the material has lower resistance to stress corrosion cracking, and lower ductility in this condition.

Heat Treatment

Solution Treatment (Condition A): Heat at 1040°C for ½ hour and cool to 30°C maximum in air. Oil quenching may be used for small non-intricate sections.


Age Hardening: After solution treatment a single low temperature "age hardening" treatment is employed to achieve required properties. This treatment results in no distortion and only superficial discolouration. A slight decrease in size takes place during the hardening

Heating and Pickling

Heating of 17-4PH material is commonly performed for heat treatment purposes. The process involves heating the material to specific temperatures and holding it for a certain duration in controlled atmospheres, and air cooling or quenching, to prevent oxidation and achieve desired mechanical propertie, improve strength and hardness. Post-treatment processes may be necessary to meet the final product specifications. 


Pickling is a common process used to remove surface impurities and oxide layers from 17-4PH stainless steel. It involves immersing the material in a pickling solution, typically an acid-based solution, to dissolve contaminants and restore the material's corrosion resistance.

Hot and Cold Forming

Hot Forming: Heat uniformly at 1742–2192°F (950–1200°C). A full solution anneal, cooling lower than 76°F (25°C) and aging at the required temperature must occur after hot forming. The post forming heat treatment should be a function of the desired mechanical properties.


Cold Forming: 17-4PH has limited cold forming properties. Cold forming can only be undertaken on plates in the fully annealed condition. Stress corrosion resistance is enhanced by re-aging at the precipitation hardening temperature after cold working.


17-4PH can be machined in both solution-annealed and precipitation-hardened conditions. Machining characteristics may vary according to the hardness of the metal. High speed tools are acceptable, but carbide tools are preferred. Due to the final hardening temperatures are low, 17-4PH can be machined to final dimensions in condition A without allowance for scaling or distortion, to save costs.


17-4PH stianless steel can be readily welded by most standard processes including SMAW, GTAW, PAW and GMAW. Favorable chemical composition accounts for the good performance of 17-4PH stainless steel in welding. Copper in the alloy is present in a form that does not affect welding behavior, The small amount of niobium that is present plays no significant part in welding. The low carbon content is an important feature for it restricts the hardness of rapidly cooled material and minimizes the chance of cracking in the weld metal and the heat-affected zone of the base metal. The low hardness eliminates the need for preheating in most applications.

Product Forms
  • Bar & Rod
  • Plate & Sheet
  • Coil & Strip
  • Pipe & Tube
  • Fitting: Flange, Tee, Elbow, Reducer etc.
  • Forging: Ring, Shaft, Circle, Block etc.

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Hunan Allianz Metal Products Co., LTD is a subsidiary company of Allianz Steel Group specializing in the supplies of special metal and related processing service, was established in 1996.
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