17-4ph Stainless Steel - Everything You Need to Know

by AMC

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Posted on January 20, 2024 at 03:57 PM

17-4PH, also known as 630 or 1.4542, stands out as one of the most popular stainless chromium-nickel alloy steels, renowned for its martensitic structure with precipitation hardening and the incorporation of copper.

This alloy is characterized by a remarkable combination of high corrosion resistance and robust strength properties, including hardness. The precipitation-hardened martensitic structure ensures enduring performance across various applications.

With a reliable operational range from -29 ℃ to 343 ℃, 17-4PH Stainless Steel demonstrates adaptability while maintaining consistent performance. This temperature versatility positions it favorably in applications requiring both strength and corrosion resistance.

Beyond its strength attributes, materials in this grade exhibit commendable ductility. Notably, their corrosion resistance aligns with that of 1.4301 / X5CrNi18-10, providing a reliable alternative in various industrial contexts.

With a typical density of 7.75 kg/dm³, 17-4PH Stainless Steel exhibits a balanced weight that contributes to its versatile applications. Notably, it can be magnetized, adding to its utility in various industrial scenarios.

17-4PH is strategically chosen for applications where an extraordinary combination of high strength and moderate corrosion resistance is pivotal. Its unique alloy composition, including precipitation hardening and the presence of copper, makes it a preferred choice in scenarios that demand exceptional mechanical properties.

17-4PH Stainless Steel Chemical Composition

Carbon	Chromium	Columbian + Tantalum	Copper	Manganese	Nickel	Phosphorus	Silicon	Sulfur
0.070 Max	15.0-17.50	0.15-0.45	3.00-5.00	1.00 Max	3.00-5.00	0.040 Max	1.00 Max	0.030 Max

17-4PH Stainless Steel Mechanical Properties

Material Type	Condition	Ultimate Tensile Strength (PSI)	0.2% Yield Strength (PSI)	Elongation (% In 2in.)	Reduction Of Area (%)	Hardness Brinell	Hardness Rockwell
17-4 PH	H900	190,000	170,000	10	40	388	C40
	H1025	155,000	145,000	12	45	331	C35
	H1075	145,000	125,000	13	45	311	C32
	H1150	135,000	105,000	16	50	277	C28
	H1150-M	115,000	75,000	18	55	255	C24
	H1150-D	125,000	105,000	16	50	255 min – 311 max	C24 – 33

A17-4PH Stainless Steel Physical Properties

Density in kg/dm3	7,8
Electrical resistance at 20°C in (Ω mm2)/m	0,71
Magnetisability	available
Thermal conductivity at 20°C in W/(m K)	16
Specific heat capacity at 20°C in J/(kg K)	500

17-4PH Stainless Steel Grade

Grade

ASTM / AISI	DIN	JIS	GB
17-4PH, 630	1.4542	SUS630	05Cr17Ni4Cu4Nb

17-4PH Stainless Steel Characteristics

Corrosion Resistance

Comparable to 304 Stainless Steel: The corrosion resistance of Type 17-4PH / 630 aligns closely with that of Type 304 Stainless Steel across most media. Notably, it surpasses the corrosion resistance of the hardenable 400 series stainless steels. For specific recommendations, consult NACE (National Association of Corrosion Engineers).

Heat Resistance

Oxidation Resistance: Grade 630 stainless steels demonstrate commendable resistance to oxidation, contributing to their durability in various applications.

Temperature Considerations: Caution is advised against prolonged exposure of grade 630 to temperatures ranging from 370 to 480°C to prevent a potential reduction in toughness at ambient temperature. Avoiding usage above the age-hardening temperature is essential to maintain hardness and mechanical properties.

Heat Treatment

Solution Treatment (Condition A): Grade 630 stainless steels undergo solution treatment at 1040°C for 0.5 hours, followed by air-cooling to 30°C. Alternatively, small sections can be oil-quenched.

Age Hardening: To achieve required mechanical properties, age hardening at low temperatures is employed. Superficial discoloration and shrinkage are anticipated during the process, with specific rates for conditions H1150 and H900.

Welding

Versatile Welding Compatibility: Grade 630 stainless steels exhibit compatibility with all conventional welding methods and do not necessitate pre-heating. Attention to design and welding practices is crucial to mitigate weldment stresses, especially in high-strength steel applications.

Machining

Machinability in Solution-Treated Condition: Grade 630 stainless steels can be machined in their solution-treated condition, with machining rates similar to that of grade 304 steels. This enhances their versatility in various machining applications.

Features of 17-4PH Stainless Steel

Excellent Corrosion Resistance:

Inox 17-4PH alloy stands out with outstanding corrosion resistance, surpassing that of any other hardenable stainless steel. In most scenarios, it matches the corrosion resistance levels of type 304 stainless steel. However, caution is advised, as stress corrosion can occur under high-strength conditions. Adjusting the stabilization temperature becomes essential to counter the risk of stress corrosion cracking.

Application-Specific Corrosion Characteristics:

While susceptible to corrosion and crack corrosion in static seawater, the alloy showcases impeccable corrosion resistance in diverse industries. Notably, in petrochemical, food processing, and paper industries, its corrosion resistance competes with that of grade 304L stainless steel.

Versatile Workability Post Solution Treatment:

In its solution-treated state, 17-4PH embodies the advantageous characteristics of austenitic steel, making it easy to work with. Its versatility extends to achieving high strength through intermediate pressure treatment and aging treatment.

Widespread Applications:

The alloy finds extensive use in critical applications such as pressure vessels, aircraft, and steam turbine blades. Particularly in components that are either in direct contact with the medium or subjected to high stress, 17-4PH excels. For instance, in applications like impellers, where corrosion resistance and mechanical properties are paramount, 17-4PH proves its mettle.

Meeting Rigorous Requirements:

The impeller, operating in direct contact with the medium, demands exceptional corrosion resistance. Simultaneously, the shaft, responsible for driving components like the impeller, requires superior strength and toughness to handle significant forces. 17-4PH emerges as the material of choice, as it seamlessly meets both the corrosion resistance and mechanical property requirements, ensuring optimal performance in demanding applications.

Applications of 17-4PH Stainless Steel

1. Offshore Platforms and Helicopter Decks: Ideal for harsh marine environments, 17-4PH is employed in the construction of offshore platforms, including helicopter decks and various other maritime platforms.
2. Food Industry: Recognized for its corrosion resistance, 17-4PH is utilized in the food industry, ensuring durability and hygiene in critical components.
3. Pulp and Paper Industry: In the pulp and paper industry, where resistance to corrosion and wear is essential, 17-4PH finds application in various components, contributing to the longevity of machinery.
4. Aerospace (Turbine Blades): Critical aerospace components, particularly turbine blades, benefit from the high strength and corrosion resistance of 17-4PH, ensuring optimal performance under demanding conditions.
5. Mechanical Components: In diverse mechanical applications, 17-4PH is preferred for its ability to offer a unique combination of strength, toughness, and corrosion resistance.
6. Nuclear Waste Barrels: The corrosion resistance and durability of 17-4PH make it suitable for use in nuclear waste barrels, ensuring the integrity of containment over extended periods.
7. Surgical Instruments: Precision and corrosion resistance are vital in surgical instruments. 17-4PH's characteristics make it a reliable choice for crafting durable and corrosion-resistant surgical tools.
8. Other Applications: The versatility of 17-4PH extends to various other applications, showcasing its adaptability in different industrial and technological settings.

Conclusion

In conclusion, 17-4PH stainless steel, with its precipitation-hardening martensitic structure and unique alloy composition, stands as a versatile material with a wide array of applications. Its excellent corrosion resistance, superior strength, and compatibility with various industries make it a preferred choice in critical environments.

From offshore platforms and aerospace components to the demanding realms of the food industry and surgical instruments, 17-4PH consistently delivers exceptional performance. The alloy's ability to withstand corrosive forces, coupled with its ease of workability post-solution treatment, positions it as a reliable solution in diverse sectors.

As we navigate the intricacies of applications like nuclear waste barrels and mechanical components, the robust characteristics of 17-4PH prove indispensable. The alloy's presence in helicopter decks, pulp and paper machinery, and the aerospace sector, particularly in turbine blades, highlights its adaptability to extreme conditions.

In essence, 17-4PH stainless steel has etched its mark as a material that seamlessly combines strength, corrosion resistance, and workability. Whether beneath the ocean waves or in the vast expanse of aerospace, 17-4PH continues to prove its mettle, contributing to the resilience and efficiency of various industrial processes and critical applications.

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