17-4 PH Specifications | |
Institute | Standard |
UNS | S17400 |
W. Nr./EN | 1.4548 |
ASTM | A693, A564, A705, Type 630 |
AMS | 5604, 5643, 5825 |
ASME | SA693, SA564, SA705, Type 630 |
NACE | MR0175 |
ISO | 15156-3 |
PH 17-4, also known as 17-4 precipitation hardening stainless steel, is a high-strength, corrosion-resistant alloy widely utilized in the manufacture of high-performance fasteners. Renowned for its exceptional mechanical properties—including high tensile strength, hardness, and excellent fatigue resistance—PH 17-4 is especially well-suited for critical fastening applications in aerospace, marine, and industrial environments. Its ability to maintain strength and dimensional stability in demanding conditions makes it a top choice for engineers seeking reliable performance.
If you’re sourcing premium-grade fasteners made from PH 17-4 stainless steel, contact Nickel Systems today to request a customized quotation tailored to your specifications.
Request a Quote
Get our technical data and information for 17-4 PH. If you questions are not answered, download the 17-4 PH Technical Data Sheet here.
17-4 PH Specifications | |
Institute | Standard |
UNS | S17400 |
W. Nr./EN | 1.4548 |
ASTM | A693, A564, A705, Type 630 |
AMS | 5604, 5643, 5825 |
ASME | SA693, SA564, SA705, Type 630 |
NACE | MR0175 |
ISO | 15156-3 |
17-4 PH Chemical Composition | ||
Element | Percent Composition | Description |
Nickel (Ni) | 3.0-5.0% | Range |
Chromium (Cr) | 15.0-17.0% | Range |
Copper (Cu) | 3.0-5.0% | Range |
Molybdenum (Mo) | 0.50% | Max |
Manganese (Mn) | 1.0% | Max |
Silicon (Si) | 1.0% | Max |
Niobium+Tantalum (Cb+Ta) | 0.45% | Max |
Carbon (C) | 0.07% | Max |
Phosphorus (P) | 0.04% | Max |
Iron (Fe) | ~ 72.66% | Balance |
17-4 PH Physical Properties | ||
Property | Value | Units |
Density | 0.282 | lb/in³ |
Melting Range | 2560-2625 | ℉ |
Poisson's Ratio | 0.272 | |
Electrical Resistivity | 463 | Ohm-circ mil/ft |
17-4 PH High Temperature Physical Properties | ||||
Temperature, ℉ | 70 | 212 | 392 | 572 |
Coefficient of Thermal Expansion, in/in℉ x 10^(-6) | - | 7.2 | 7.5 | 7.8 |
Thermal Conductivity, Btu●ft/ft²●hr●℉ | 8.6 | 9.2 | 9.8 | 10.4 |
Modulus of Elasticity Dynamic, psi x10^(6) | 29.0 | 28.1 | 27.0 | 26.1 |
17-4 PH Mechanical Properties | ||||||
0.2% Yield Strength, ksi | Ultimate Tensile Strength, ksi | % Elongation | Reduction in Area, % | Hardness, Brinell / Rockwell | Impact Charpy V-Notch, ft-lbs | |
H900 | 185 | 200 | 14 | 50 | 420 / C 44 | 15 |
H925 | 175 | 190 | 14 | 54 | 409 / C 42 | 25 |
H1025 | 165 | 170 | 15 | 56 | 352 / C 38 | 35 |
H1075 | 150 | 165 | 16 | 58 | 341 / C 36 | 40 |
H1100 | 135 | 150 | 17 | 58 | 332 / C 35 | 45 |
H1150 | 125 | 145 | 19 | 60 | 311 / C 33 | 50 |
H1150D | 120 | 140 | 22 | 65 | 294 / C 31 | 55 |
H1150-M | 85 | 125 | 22 | 68 | 277 / C 27 | 100 |
17-4 PH Heat Treatment Processes | |
Type | Processing |
H900 | Condition A material is heated at 900℉ +/- 25℉ for 1/2 hour, air (Solution Treated) cooled or oil quenched to below 90℉. This is normally performed at the mill. |
H925, H1025, H1075, H1100, H1150 | Condition A material is heated 4 hours at 1150℉ +/- 15℉ for 1 hour and air cooled. Maximum hardness but low toughness. Sensitive to stress corrosion cracking. Heating 4 hours improves toughness while decreasing the tensile and yield strengths by about 4ksi. |
H1150D | Condition A material heated 4 hours at 1150℉, air cooled, heated again for an additional 4 hours at 1150℉ and air cooled |
H1150-M | Condition A material heated at 1400℉ +/- 25℉ for 2 hours, air cooled, then heated at 1150℉ +/- 15℉ for 4 hours and air cooled |
17-4 PH, also known as PH 17-4 or UNS S17400, is a precipitation-hardening martensitic stainless steel that combines high strength, hardness, and moderate corrosion resistance. The “17-4” refers to its composition—17% chromium and 4% nickel—with small additions of copper and niobium (or columbium), which help it achieve excellent mechanical properties through heat treatment.
High Strength: Can achieve tensile strengths up to 200 ksi (1,380 MPa) depending on heat treatment (e.g., Condition H900).
Corrosion Resistance: Comparable to 304 stainless steel in many environments; suitable for mild to moderately aggressive settings.
Good Toughness: Retains impact strength and ductility in various heat-treated states.
Heat Treatable: Strength and hardness are developed by a single low-temperature aging treatment (e.g., 900–1150°F / 482–621°C).
Excellent Dimensional Stability: Minimal distortion during heat treatment makes it ideal for precision parts.
Check out our chemical composition pie chart for 17-4 PH and find out how each element impacts strength and its corrosion resistance.
17-4 PH (Precipitation Hardening) stainless steel is a martensitic stainless steel that combines high strength and hardness with moderate corrosion resistance. Its corrosion behavior is influenced by its composition and heat treatment condition.
17-4 PH exhibits moderate resistance to general corrosion in atmospheric and mildly corrosive environments. It performs between than many standard stainless steels but worse than austenitic stainless steels like 304 and 316. Chromium forms a passive chromium oxide layer and is the primary defense against uniform corrosion. Nickel also helps against certain types of acidic environments.
17-4 PH does not perform well against pitting corrosion. It is susceptible to pitting corrosion especially in chloride-containing environments. This is due to its low molybdenum content.
17-4 PH is also vulnerable to crevice corrosion in tight joints especially in stagnant water.
17-4 PH is susceptible to stress corrosion cracking especially in chloride-rich environments when under tensile stress.
17-4 PH shows good resistance to intergranular corrosion when it is fully heat-treated.
Galvanic corrosion can occur if 17-4 PH is combined with more noble alloys such as Titanium or 316 Stainless.
Get more information on our blog: Types of Corrosion
One of the most fundamental characteristics of 17-4 PH stainless steel is its strength. It offers a rare combination of high strength, hardness and corrosion resistance especially when it is heat treated. The primary mechanism responsible for 17-4 PH’s strength is its solution treatment at 1900℉ in which the alloy is homogenized to dissolve alloying elements into the matrix. This is then followed by a controlled aging process at 900-1150℉. When this is done, a fine intermetallic precipitates form. Next the material is air cooled. When this occurs, 17-4 PH is transformed into a martensitic microstructure. It becomes very hard and brittle adding both strength and hardness.
17-4 PH Strength Comparison with other Stainless Steels | ||
Material | Ultimage Tensile Strength | 0.2% Yield Strength |
17-4 PH (H900) | ~ 275 ksi | ~ 220 ksi |
17-4 PH (H1150) | ~ 135 ksi | ~ 115 ksi |
410 Stainless Steel | ~ 112 ksi | ~ 65 ksi |
~ 84 ksi | ~ 42 ksi | |
~ 90 ksi | ~ 35 ksi | |
17-4 PH stainless steel is widely used in aerospace, marine, energy, and chemical processing industries due to its combination of high strength, good corrosion resistance, and excellent mechanical properties up to 600℉. Below is a breakdown of specific applications and the fasteners employed.
The aerospace industry uses 17-4 PH fasteners in aircraft structural components, landing gear assemblies, jet engine mounts and frames, and helicopter shafts and actuators. Specifically, Hex Head Cap Screws are used to secure structural and load-bearing parts in airframes and gear assemblies. 12-point flange screws are used in turbine housings and engine assemblies due to their high clamping force. Socket head cap screws are used where space constraints exist. This includes avionics and control surfaces. Countersunk flat head screws are used in applications with flush surfaces especially exterior panels and internal compartments.
The marine industry uses 17-4 PH fasteners in propeller shafts and pump shafts, submarine pressure hulls, underwater equipment, and naval valve components. 17-4 PH hex head cap screws are used to assemble corrosion-resistant housings and brackets. 17-4 PH washers are used to distribute load and reduce surface damage in submerged environments. Heavy hex bolts and heavy hex nuts are used in structural assemblies that are exposed to vibrations & saltwater. Socket set screws are used to lock marine shaft components in place.
The oil and gas industries use 17-4 PH fasteners in their valve components, pump housings, manifolds, and offshore platform assemblies. They utilize studs with heavy hex nuts in high-pressure flange connections. Socket head cap screws are used in pump casings and high-strength manifolds. Hex flange screws are used in vibration-intensive locations of rotating machinery. They use threaded rods to fasten subsea pressure vessels and piping clamps.
17-4 PH stainless steel is a high-performance alloy that delivers a unique combination of exceptional strength, corrosion resistance, and reliability across a wide range of demanding industries. Whether used in aerospace structures, marine equipment, oilfield tools, or precision medical instruments, its ability to maintain mechanical integrity under stress and corrosive environments makes it an ideal choice for mission-critical fastener applications. With its versatility in heat treatment and a wide variety of available fastener forms—such as hex head cap screws, 12-point flange bolts, and finished hex nuts—17-4 PH is a top-tier solution for engineers and procurement professionals alike.
Looking for premium 17-4 PH fasteners tailored to your application? Contact Nickel Systems today for a fast, customized quote and expert support to help you get the right products for your performance-critical needs.
