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Stainless Steel 17-4PH

17-4PH is a widely-used martensitic precipitation-hardening stainless steel with a high concentration of chromium and nickel. It has many favorable properties, including excellent strength, good corrosion resistance, and excellent mechanical properties up to 600 °F (316 °C).

The alloy also possesses good toughness when welded, while short low-temperature heat treatments reduce warping and scaling. Additionally, 17-4PH is easy to machine and fabricate.

Thanks to the beneficial properties, 17-4PH finds use in various industries. Typical parts include mechanical seals, oil patch, and pump shafts.

Furthermore, the alloy also finds use in the aerospace industry, petroleum industry, and chemical industry, food processing equipment, paper and pulp industry, nuclear waste processing and storage, and general metalworking.

Tech Steel & Materials offers Stainless Steel 17-4PH in two sub-type specifications and multiple shapes/forms:

  • AMS 5604 (Plate, Sheet, and Strip)
  • AMS 5643 (Bar, Forging, Ring, Tubing, and Wire)

Stainless Steel 17-4PH Chemical Composition

Element Min (%) Max (%)
Carbon, C 0.07
Manganese, Mn 1
Silicon, Si 1
Sulfur, S 0.03
Phosphorus, P 0.04
Chromium, Cr 15 17.5
Niobium + Tantalum, Nb + Ta 0.15 0.45
Nickel, Ni 3.0 5.0
Copper, Cu 3.0 5.0
Iron, Fe *Balance

*Not exclusively to the element mentioned, but that one predominates other elements that are used in smaller quantities.

Fabrication and Working Instructions

Stainless Steel 17-4PH reacts best to hot forming at 1742 to 2192 °F (950 to 1200 °C), with annealing at 76 °F (25 °C) and aging. The alloy can also be cold-formed in limited form, primarily to plates in the annealed condition. However, stress corrosion resistance can be improved with re-aging.

Furthermore, 17-4PH can be cut using mechanical operations, such as abrasive waterjets, machining, bandsaw, and shearing. However, plasma cutting isn’t recommended on this alloy.

17-4PH has the best welding characteristics of competing stainless steel alloys. Moreover, it can be welded using all standard techniques, including gas tungsten arc, gas metal arc, shielded metal arc, and plasma arc. To achieve desired mechanical properties, pre-weld and post-weld heat treatments are recommended. For the best results, we recommend the AMS 5643 wire.

Physical Properties of Stainless Steel 17-4PH

Property Imperial Metric
Melting Range 2560-2625 °F 1404-1440 °C
Specific Heat 0.11 Btu/lb.-°F 460 Joules/gg-K
Specific Density 0.282 lb/in3 7.8 g/cm3
Electrical Resistivity 38.6 µΩ in 98 µΩ cm
Linear Coefficient of Thermal Expansion (70 °F to 200 °F) (21 °C to 93 °C) 6 [in/in/°F·106] 10.8 [μm/m·°C]
Linear Coefficient of Thermal Expansion (70 °F to 400 °F) (21 °C to 204 °C) 6 [in/in/°F·106] 10.8 [μm/m·°C]
Linear Coefficient of Thermal Expansion (70 °F to 600 °F) (27 °C to 316 °C) 6.2 [in/in/°F·106] 11.2 [μm/m·°C]
Linear Coefficient of Thermal Expansion (70 °F to 800 °F) (21 °C to 427 °C) 6.3 [in/in/°F·106] 11.2 [μm/m·°C]
Thermal Conductivity (@ 300 °F) (@ 149 °C) 124 Btu/(hr/ft²/in/°F) 17.9 [W/m-K]
Thermal Conductivity (@ 500 °F) (@ 260 °C) 135 Btu/(hr/ft²/in/°F) 19.5 [W/m-K]
Thermal Conductivity (@ 860 °F) (@ 460 °C) 156 Btu/(hr/ft²/in/°F) 22.5 [W/m-K]
Thermal Conductivity (@ 900 °F) (@ 482 °C) 157 Btu/(hr/ft²/in/°F) 22.6 [W/m-K]
Poisson’s Ratio (H900 Condition) 0.272 0.272
Modulus of Elasticity (H900 Condition) 28 x 106 ksi 197 x 103 MPa
Modulus of Rigidity in Torsion 9.68 x 103 ksi 67 x 103 MPa

Stainless Steel 17-4PH Mechanical Properties

Property Imperial Metric
Ultimate Tensile Strength 23,300 psi 160 MPa
Yield Strength (0.02%) 16,680 psi 115 MPa
Elongation (% in 2’’) 5% 5%
Rockwell Hardness C 35 35

Heat Treatment

Stainless Steel 17-4PH is available in the solution annealed condition at 1900 °F (1038 °C) and then air-cooled to 90 °F (32 °C).

However, additional heat treatments can produce various hardness and toughness levels. The most common treatments are listed in the table below.

Condition Temperature [± 15 °F (± 8.4 °C)] Cooling Method and Duration
H 900 900 °F (482 °C) Air cooling for 1 hour
H 925 925 °F (496 °C) Air cooling for 4 hours
H 1025 1025 °F (551 °C) Air cooling for 4 hours
H 1075 1075 °F (580 °C) Air cooling for 4 hours
H 1100 1100 °F (593 °C) Air cooling for 4 hours
H 1150 1150 °F (621 °C) Air cooling for 4 hours
H 1150 + 1150 1150 °F (621 °C)
followed by
1150 °F (621 °C)
Air cooling for 4 hours
followed by
Air cooling for 4 hours
H 1150-M 1400 °F (760 °C)
followed by
1150 °F (621 °C)
Air cooling for 2 hours
followed by
Air cooling for 4 hours

Select AMS Number:

AMS Number Alloy Type UNS Cross Ref. Spec Misc./Shape
AMS 5604 17-4PH Stainless Steel S17400  
AMS 5604 Plate 17-4PH Stainless Steel S17400 - Plate AMS 5604 Plate
AMS 5604 Sheet 17-4PH Stainless Steel S17400 - Sheet AMS 5604 Sheet
AMS 5604 Strip 17-4PH Stainless Steel S17400 - Strip AMS 5604 Strip
AMS 5643 17-4PH Stainless Steel S17400  
AMS 5643 Bar 17-4PH Stainless Steel S17400 - Bar AMS 5643 Bar
AMS 5643 Forging 17-4PH Stainless Steel S17400 - Forging AMS 5643 Forging
AMS 5643 Ring 17-4PH Stainless Steel S17400 - Ring AMS 5643 Ring
AMS 5643 Tubing 17-4PH Stainless Steel S17400 - Tubing AMS 5643 Tubing
AMS 5643 Wire 17-4PH Stainless Steel S17400 - Wire AMS 5643 Wire