ThePipingMart Blog Grades 17-4 Stainless Steel (UNS S17400) – Composition, Properties, and Uses

17-4 Stainless Steel (UNS S17400) – Composition, Properties, and Uses

17 4 Stainless Steel

17-4 stainless steel is a martensitic, chromium-nickel-copper precipitation-hardening stainless steel. It has high strength and good corrosion resistance, making it an ideal choice for many industrial applications. This blog post will take a closer look at the properties and uses of 17-4 stainless steel.

What Forms is 17-4 Stainless Steel Available at Piping Mart?

  • 17-4 Stainless Steel Pipes
  • 17-4 Stainless Steel Tubing
  • 17-4 Stainless Steel Bars
  • 17-4 Stainless Steel Bolts
  • 17-4 Stainless Steel Screw
  • 17-4 Stainless Steel Pipe Fittings
  • 17-4 Stainless Steel Foil
  • 17-4 Stainless Steel Coil

Types of 17-4 Stainless Steel

17-4 stainless steel comes in Type 630 and Type 631. Type 630 is annealed and hardened by heating to temperatures between 900°F (482°C) and 1150°F (621°C). This type is usually used for general-purpose parts with high strength and corrosion resistance. Type 631 is annealed and hardened by heat treating to temperatures between 1275°F (690°C) and 1325°F (720°C). This type is usually used for parts that require higher strength than the Type 630 but are less corrosion-resistant.

17-4 Stainless Steel Composition

SS 17-4 is a type of Inconel sheet that has a unique composition. It is composed primarily of iron, chromium, and nickel. Additionally, it contains 17%-4% copper, manganese, silicon, and carbon. This combination of elements makes 17-4 stainless steel incredibly strong, very corrosion resistant, and exceptionally ductile as temperatures start to increase. The high levels of nickel also contribute to its low-magnetic properties while copper helps with its great resistance to stress-corrosion cracking. Its alluring qualities ensure that the 17-4 stainless steel Inconel sheet will continue to be an excellent choice for a variety of construction projects that require long-lasting strength and durability.

Element Content (%)
Iron, Fe 73
Chromium, Cr 15.0 – 17.5
Nickel, Ni 3.0 – 5.0
Copper, Cu 3.0 – 5.0
Manganese, Mn 1.0
Silicon, Si 1.0
Tantalum, Ta 0.45
Niobium, Nb (Columbium, Cb) 0.45
Nb + Ta 0.15 – 0.45
Carbon, C 0.070
Phosphorous, P 0.040
Sulfur, S 0.030

17-4 Stainless Steel Physical Properties

stainless steel 17-4 is a sophisticated material that features an incredible combination of physical properties. It is a commonly used Inconel sheet, renowned for its corrosion resistance, high-temperature strength, and toughness. This unique alloy offers excellent levels of fatigue and corrosion resistance, as well as a hardness value of 47 on the Rockwell “C” scale. With its superior toughness, 17-4 stainless steel provides durable protection from scratches or abrasions in challenging environments. Additionally, its cryogenic properties make it ideal for applications that require extended operational exposure to cold temperatures. The versatile nature of 17-4 stainless steel makes it an ideal choice for those in need of reliable metal products with superior physical properties.

Properties Metric Imperial
Density 7.75 g/cm3 0.280 lb/in³

17-4 Stainless Steel Mechanical Properties

17-4 stainless steel is a remarkable metal, with incredible mechanical properties that make it perfect for both structural and aesthetic applications. It has a low coefficient of friction, allowing for ease of forming, welding, and machining, making it suitable for parts requiring high levels of repeatability. As an Inconel sheet, it is highly resistant to stress-cracking corrosion caused by chlorides. It also performs well in cryogenic environments and offers excellent thermal stability when exposed to temperatures up to 600 degrees Celsius. With such impressive characteristics, 17-4 stainless steel is the metal of choice for many industries requiring tough construction and exceptional performance standards.

Properties Metric Imperial
Shear modulus 77.4 GPa 11200 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell 352 352
Hardness, Knoop (estimated from Rockwell C) 363 363
Hardness, Rockwell C 36 36
Hardness, Vickers (estimated from Rockwell C) 349 349

17-4 Stainless Steel Specifications

  • AISI 630
  • AMS 5604
  • AMS 5622
  • AMS 5643
  • ASTM A564 (630)
  • ASTM A693 (630)
  • ASTM A705 (630)
  • MIL C-24111
  • MIL P-47183
  • MIL S-81591
  • UNS S17400

17-4 Stainless Steel Properties

UNS S17400 has excellent mechanical properties due to its high strength. It is ideal for many industrial applications, such as medical equipment, automotive components, food processing machinery, aerospace parts, marine hardware, machine tools, and more. It also has excellent corrosion resistance due to its high nickel content, which helps resist rusting in acidic environments. Additionally, 17-4 stainless steel can be cold-worked or machined easily due to its softness even after heat treatment.

Corrosion Resistance

One of the primary benefits of 17-4 stainless steel is its high corrosion resistance. This type of steel can resist corrosion in various environments, including both acidic and basic conditions. Additionally, 17-4 stainless steel is resistant to chloride and sulfate corrosion.

High Strength

S17400 also has a high strength-to-weight ratio. This means that it is strong enough to be used in applications where weight is a concern, such as in the aerospace industry. Additionally, this type of steel has a high yield strength, making it ideal for use in components subject to high-stress levels.

Good Thermal Conductivity

Another benefit of 17-4 stainless steel is its good thermal conductivity. This property makes it ideal for use in applications where heat needs to be transferred quickly, such as in heat exchangers. Additionally, this type of steel has a low coefficient of thermal expansion, which means that it will not expand or contract significantly when exposed to changes in temperature.


Another advantage of 17-4 stainless steel is that it is non-magnetic. This property makes it ideal for use in applications with undesirable magnetic properties, such as food processing equipment or medical devices. Additionally, this type of steel is resistant to magnetostriction, meaning it will not become magnetized when exposed to a magnetic field.

Good weldability

SS 17-4 also has good weldability. This means it can be quickly joined to other types of metals using welding methods such as arc welding and gas tungsten arc welding. Additionally, this type of steel can be welded using conventional and filler metals.

17-4 Stainless Steel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 21-93°C/69.8-199°F) 10.8 µm/m°C 6.00 µin/in°F
Thermal conductivity ( for condition H 900 at 149ºC. 22.6 W/mK for H 900 at 482ºC) 17.9 W/mK 124 BTU in/hr.ft².°F

17-4 Stainless Steel Equivalent

Other designations that are equivalent to grade 17-4 stainless steel are listed in the following table.

AISI 630 ASTM A693 (630) AMS 5342 MIL-S-81506
AMS 5604 ASTM A705 (630) AMS 5343 SAE J467 (17-4PH)
AMS 5622 MIL C-24111 AMS 5344 ASME SA705
AMS 5643 MIL P-47183 AMS 5355 ASME SA564
ASTM A564 (630) MIL S-81591 AMS 5825

17-4 Stainless Steel Uses

Due to its strong mechanical properties and corrosion resistance, 17-4 stainless steel is used in various automotive and aerospace industries. It is commonly used in medical devices such as implants because they require materials with high mechanical strength that can withstand sterilization processes without rusting over time. Additionally, it is often used in the manufacturing of food processing machinery because it offers excellent corrosion resistance when exposed to acidic ingredients like vinegar or citrus fruits. It’s also widely used in aerospace because it can withstand extreme temperatures without losing its mechanical properties or rusting.


In conclusion, 17-4 stainless steel has many beneficial properties that make it suitable for use in various automotive and aerospace industries. Its high strength and good corrosion resistance make it an ideal choice for those looking for a material that can withstand extreme conditions while maintaining its mechanical properties over time. Whether you’re looking for a material for medical devices or food processing machines, consider using 17-4 stainless steel – you won’t be disappointed!

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