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Everything You Should Know About 17-4 PH Stainless Steel

Views: 6     Author: Wang     Publish Time: 2024-05-24      Origin: Site

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Benefits of 17-4 Stainless Steel

17-4PH is a nickel-chromium precipitation-hardening stainless steel suitable for applications requiring much higher strength, toughness and good corrosion resistance. The alloy offers various attractive performance characteristics. The material possesses good stress corrosion resistance, high fatigue resistance and resistance to galling. 17-4PH is readily weldable by all conventional methods, and there is no requirement for pre or post-heating, which is usually the case for standard hardenable stainless steels. A single, low-temperature heat treatment will harden the alloy.

This grade of stainless steel has a typical density of 7.75kg/dm³ and can be magnetised. 17-4PH finds specific use in applications where a combination of unusually high strength and moderate corrosion resistance is a determining factor. The alloy has similar corrosion resistance characteristics when compared to 304 stainless steel. 17-4PH is highly suitable for applications where the production of intricate parts is a requirement, especially if these parts require machining, welding and have freedom from distortion. Examples include aircraft structural parts, high-performance fasteners, pump shafts, valve stems and gears.

Alloy 17-4PH (UNS S17400), Type 630, is a chromium-nickel-copper precipitation-hardening martensitic stainless steel with an addition of niobium. 17-4PH combines high strength and hardness with good corrosion resistance. The alloy is furnished in the solution annealed condition (Condition A). It should not be used at temperatures above 572°F (300°C) or for cryogenic service. Optimal mechanical properties can be obtained by subjecting the alloy to age hardening heat reatments. Heat treatment in the 900°F (482°C) range produces the highest strength. The corrosion resistance of Alloy 17-4PH is omparable to 304 stainless steel in most environments, and is generally superior to the 400 series stainless steels. It is used in applications where the combination of moderate corrosion resistance and unusually high strength are required. Alloy 17-4PH can be easily welded and processed by standard shop fabrication practices.

Chemical Composition of 17-4 Stainless Steel

Stainless steels 17-4PH is known as high-alloy steels. They contain about 4-30% of chromium. They are further divided into martensitic, austenitic, and ferritic steels. Another group of stainless steels are known as precipitation-hardened steels. They are a combination of austenitic and martensitic steels. Grade 17-4 stainless steel is the most widely used steel of the precipitation hardening grade steels. It has high toughness, strength, and corrosion resistance. The following table shows the chemical composition of grade 17-4 stainless steel.


Content (%)

Iron, Fe


Chromium, Cr

15.0 - 17.5

Nickel, Ni

3.0 - 5.0

Copper, Cu

3.0 - 5.0

Manganese, Mn


Silicon, Si


Tantalum, Ta


Niobium, Nb (Columbium, Cb)


Nb + Ta

0.15 - 0.45

Carbon, C


Phosphorous, P


Sulfur, S


Features of 17-4PH Stainless Steel

High-alloy steels like 17-4PH Stainless Steel offer many advantages over other metals for a variety of needs. Key features include:

17-4 PH Stainless Steel Density

The density of 17-4PH stainless steel is 0.280 lb/in3 (7.8 g/cm3), which makes it an ideal material for many applications that require high strength and corrosion resistance.

17-4 PH Stainless Steel Hardness

One of the most important properties of 17-4 PH is that it offers superior hardness when heat treated, making it an ideal choice for applications that require high strength and wear resistance.

17-4PH Stainless Steel Corrosion resistance

when the mechanical properties and corrosion resistance of martensitic steels are insufficient, the 17-4PH is suitable for use in marine environments. It has a combination of very good mechanical properties and corrosion resistance. In standing seawater, 17-4PH is susceptible to crevice corrosion. This requires additional protection.

17-4 PH Stainless Steel Machinability

17-4 PH can be machined in the hardened and solution-annealed condition. Depending on the hardness, the machinability varies, this will depend on the condition. 17-4PH stainless steel is highly versatile due to its machinability. The metal alloy can be used for a wide variety of purposes and applications across industries.

17-4 PH Stainless Steel Heat Treatment

Also called precipitation hardening, age hardening uses existing particles or solid impurities to increase the strength of an alloy. 17-4PH stainless steel is well-suited for this process. To age harden 17-4PH stainless steel, you would first use a solution treatment, then quenching and aging. The treatment needs to be performed at 1050 °C for 30 minutes. To complete precipitation hardening, the temperature ranges from 480 °C to 760 °C and usually takes two to four hours.If no after-heat treatment takes place, the mechanical-technological values in the weld seam and the heat-affected zone to the base material can be very different.

17-4 PH Stainless Steel Welding

Before the material 17-4PH can be welded, consideration must be given to the condition of the base material. In stable form, copper is present in the material. This promotes no hot cracking. To be able to do the welding optimum welding conditions are required. Undercuts or welding defects can lead to the formation of a notch. That should be avoided. To prevent the formation of stress cracks, the material must be subject again to solution annealing with subsequent aging within a very short time after welding.

17-4 PH Stainless Steel Forging

The forging of the material takes place in a temperature range of 1180 ° C to 950 ° C. To ensure grain refining, the cooling to room temperature is done with air.

What Is 17-4PH Stainless Steel Used For?

17-4PH stainless steel is known for its high strength, corrosion resistance, and toughness. Because of these traits, it is often used in the aerospace, medical, and food processing industries, as well as in construction, oil and gas, and transportation. Additionally, 17-4 PH stainless steel is often used in the manufacturing of gears, valves, pumps, and fasteners, as well as in the production of molds and dies. The alloy’s high strength and corrosion resistance properties make it an ideal material for use in harsh and demanding environments.

Oil and Gas

17-4PH stainless steel is a good choice for the oil and gas industry because of its ability to withstand harsh conditions and corrosive environments. The alloy is highly resistant to corrosion caused by saltwater and chemicals, making it well suited for use in offshore and coastal environments. Additionally, 17-4PH stainless steel has a high strength-to-weight ratio, which makes it ideal for use in the oil and gas industry where weight and size are often critical factors.


17-4PH stainless steel contains molybdenum, which increases its corrosion resistance and improves its mechanical properties. Suitable for marine or coastal environments, 17-4PH steel resists chloride ion corrosion or saltwater corrosion. For applications that require moderate corrosion resistance, 17-4PH that provides good overall performance. Like 304 stainless steel, 17-4PH is suited for valves, dies, screws, and fasteners.


17-4 PH is useful in the aerospace industry because it has excellent resistance to corrosion and great tensile strength. Such advantages are critical since airplane components and parts, as well as various aerospace equipment, must operate in a variety of environments and temperatures, making corrosion resistance with high strength essential.

Food Processing

In the food processing industry, corrosion-resistant 17-4PH stainless steel is often used in the production of food processing equipment, such as storage tanks, conveyors, and processing machinery. The alloy is magnetic, making it ideal for use in food environments where magnets are used to ensure contaminants are removed. Additionally, the high strength and durability of 17-4PH stainless steel make it well suited for use in applications that require frequent sanitation and cleaning processes.

Paper / Pulp

In the paper and pulp industry, 17-4PH stainless steel is used when creating equipment that processes pulp such as tanks, pumps, valves, and heat exchangers. Because the parts may be exposed to high temperatures, it’s important to use a resilient alloy like 17-4PH.

Nuclear Industry

Every nuclear sector needs to utilize stainless steel. Nuclear power plants must deal with water, fuel, and chemicals to create electricity. As a result, they must employ a 17-4 stainless steel bar with strong corrosion resistance and outstanding toughness. Stainless steel grade 17-4 PH is valuable to make dry casks. The dry cask’s construction uses a 17-4 PH round bar and 17-4 PH stainless steel screws, guaranteeing that the spent nuclear fuel is kept securely.

JN Alloy is a distributor and product manufacturer of stainless steel, duplex steel, and nickel.
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Add: Stainless steel Market 289, Xinwu District , Wuxi, China
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