Difference of UNS32750 UNS32760

UNS S32750 and UNS S32760 are both super duplex stainless steel grades used where ordinary stainless steel types may not provide enough strength or chloride corrosion resistance. The practical difference is that UNS S32750 is the more widely specified 2507-type grade, while UNS S32760 is a copper- and tungsten-bearing super duplex option often chosen for especially aggressive acid, seawater, and oil and gas service. If you are comparing uns32750 vs uns32760, the right choice depends less on the name and more on the environment, product form, project standard, welding plan, and availability.

Which grade should you choose?

चुनीं UNS S32750 when the project needs a proven super duplex stainless steel with high strength, strong resistance to chloride stress corrosion cracking, and broad availability across common product forms. Choose UNS S32760 when the service environment gives extra value to copper and tungsten additions, especially where specifications call for F55/Zeron 100-type material or where resistance to non-oxidizing acids, strong alkalis, or warm seawater conditions is a key concern. Alleima describes SAF 2507, UNS S32750, as a super-duplex austenitic-ferritic stainless steel for highly corrosive service, while Rolled Alloys describes ZERON 100, UNS S32760, as a highly alloyed super duplex stainless steel for aggressive environments. (alleima.com)

A simple decision summary looks like this:

• Best general super duplex choice: UNS S32750, especially when drawings, stock lists, or procurement routes already favor 2507/F53.
• Best choice for specified F55/Zeron 100-type service: UNS S32760, especially when the design basis values copper and tungsten additions.
• Best procurement starting point: Confirm the governing ASTM, ASME, EN, NACE, or project specification before comparing supplier offers.
• Best engineering practice: Do not substitute one for the other just because both are super duplex steel grades; check chemistry, mechanical requirements, corrosion assumptions, welding procedure, and certification.

Comparison of UNS S32750 and UNS S32760 super duplex stainless steel pipes

The main difference is alloy chemistry

Both grades sit in the super duplex family, which means they combine ferritic and austenitic stainless steel characteristics. This mixed microstructure is the reason these duplex steel grades can offer high strength along with strong chloride corrosion resistance. In broad terms, both are built around high chromium, nickel, molybdenum, and nitrogen content, but UNS S32760 adds deliberate tungsten and copper ranges that distinguish it from the standard 2507-type chemistry.

खातिर UNS S32750, the common identity is 2507 or F53, with EN number 1.4410. Alleima lists SAF 2507 as UNS S32750 and EN 1.4410, with the EN name X 2 CrNiMoN 25-7-4.  Its nominal composition is typically understood around 25% chromium, about 7% nickel, molybdenum near the 4% class, and nitrogen for duplex phase balance and pitting resistance.

खातिर UNS S32760, the common identity is Zeron 100 or F55, with EN number 1.4501. Rolled Alloys lists ZERON 100 as UNS S32760 and W.Nr./EN 1.4501, and its data book gives wrought composition ranges including chromium 24.0–26.0%, nickel 6.0–8.0%, molybdenum 3.0–4.0%, tungsten 0.5–1.0%, copper 0.5–1.0%, and nitrogen 0.2–0.3%.

Compared by chemistry, the key points are:

• Chromium: Both grades are in the 25% chromium super duplex range, supporting passivation and oxidation resistance.
• Nickel: Both use nickel to help stabilize the austenitic phase within the duplex structure.
• Molybdenum: Both include molybdenum for pitting and crevice corrosion resistance in chloride-bearing media.
• Nitrogen: Both rely on nitrogen to support strength, phase balance, and localized corrosion resistance.
• Copper: UNS S32760 includes copper as a defining addition; UNS S32750 is not usually selected for copper-bearing performance.
• Tungsten: UNS S32760 includes tungsten as a defining addition; UNS S32750 does not normally have tungsten as a central alloying feature.

Corrosion performance separates the use cases

Corrosion resistance is the main reason engineers compare these two duplex stainless steel grades. Both grades are designed for difficult environments, but their practical positioning is not identical. UNS S32750 is often selected as a strong general-purpose super duplex stainless steel for chloride environments, while UNS S32760 is often selected where the extra alloying package better matches the chemical exposure.

Alleima characterizes UNS S32750 as having excellent resistance to chloride stress corrosion cracking, pitting, crevice corrosion, general corrosion, erosion corrosion, and corrosion fatigue.  That makes it suitable for many marine, chemical processing, heat exchanger, and oil and gas applications when the governing design code and environmental limits support it.

Rolled Alloys notes that the copper content in ZERON 100 gives excellent resistance to many non-oxidizing acids and that the alloy is highly resistant to strong alkalis. This is the practical reason many comparisons favor UNS S32760 in more severe chemical service, not because UNS S32750 is weak, but because S32760 has extra alloying tools for certain environments.

A useful corrosion comparison is:

• Chloride stress corrosion cracking: Both grades are strong choices compared with many austenitic stainless steel types.
• Pitting and crevice corrosion: Both are super duplex options with high resistance; grade selection should consider actual temperature, chloride level, acidity, and crevice geometry.
• Non-oxidizing acids: UNS S32760 may have an advantage because of its copper content.
• Strong alkalis: UNS S32760 is commonly promoted for this service area.
• General seawater and offshore exposure: Both can be relevant, but UNS S32760 is frequently specified in demanding seawater, subsea, and process systems when F55 is required.

Which option is easier to source and specify?

UNS S32750 is often easier to source because it is one of the most recognized super duplex stainless steel options, commonly associated with 2507 and F53. UNS S32760 is also available in many industrial product forms, but it is more specialized, so lead time, mill source, certification, and approved manufacturer lists may become more important. In procurement terms, S32750 often wins on simplicity, while S32760 often wins when the project specification already calls for F55/Zeron 100-type material.

When comparing supply, use the same checklist for both grades:

1. Confirm the exact UNS number. Do not accept “super duplex” as a complete material description.
2. Match the product standard. Pipe, tube, plate, bar, fittings, flanges, and forgings may be controlled by different standards.
3. Check grade equivalents carefully. UNS S32750 is commonly linked with F53 and 1.4410; UNS S32760 is commonly linked with F55 and 1.4501.
4. Review certificates. Require heat number, chemical composition, mechanical properties, heat treatment condition, and any project-specific testing.
5. Verify corrosion service requirements. If NACE, sour service, seawater, or chemical plant rules apply, substitution needs engineering approval.

Rolled Alloys lists ASTM and ASME specifications for ZERON 100, including ASTM A182 Grade F55 and several common wrought product standards.  Alleima lists UNS S32750 as suitable for further production according to ASTM A182 Grade F53 in its billet datasheet context.

Mechanical strength and fabrication are broadly similar

Both grades are selected when strength matters. Super duplex stainless steel generally offers higher strength than many common austenitic stainless steel types, which can support thinner sections, lighter equipment, or greater design margins when codes allow. That does not mean either grade is automatically interchangeable, because mechanical properties depend on product form, thickness, heat treatment, standard, and manufacturer certification.

Fabrication also needs discipline. Duplex stainless steel must be welded with control over heat input, interpass temperature, filler selection, and post-weld cleaning so the ferrite-austenite balance and corrosion resistance are not damaged. Rolled Alloys specifically states that ZERON 100 is welded using ZERON 100X filler metal, which highlights why filler selection should follow the material supplier, welding procedure, and project specification rather than generic stainless practice.

For fabrication comparison:

• Forming: Both grades can be formed, but higher strength means more forming force than many austenitic grades.
• Machining: Both can be machined with suitable tooling, speeds, feeds, and coolant strategy; work hardening and toughness must be managed.
• Welding: Both require qualified procedures designed for super duplex materials.
• Heat exposure: Extended exposure to elevated temperatures can reduce toughness in super duplex alloys; Rolled Alloys notes ZERON 100 is not recommended for extended exposure above 600°F.

UNS32750 vs UNS32760 by application

In real projects, the application usually decides the grade faster than a chemistry list. UNS S32750 is often appropriate when a project needs a robust, widely recognized super duplex material for chloride-bearing fluids, offshore components, heat exchangers, process equipment, or high-strength stainless parts. It is a practical default among super duplex steel grades when the environment is severe but does not specifically demand the copper-tungsten chemistry of S32760.

UNS S32760 is often appropriate when the design specification calls for F55, Zeron 100-type chemistry, or enhanced performance in aggressive process environments. Rolled Alloys lists oil and gas applications for ZERON 100 such as process, seawater, firewater and subsea pipework systems, plus risers, manifolds, pressure vessels, valves, and heat exchangers. (rolledalloys.com) That application profile explains why S32760 appears often in offshore and chemical service discussions.

Practical selection by use case:

• General super duplex piping: Start with UNS S32750 unless the project specification or corrosion review points to S32760.
• Seawater systems: Consider both, then evaluate temperature, chlorides, crevice risk, flow, and standards.
• Chemical processing: Consider UNS S32760 when non-oxidizing acids or strong alkalis are part of the service.
• Oil and gas: Follow project specifications, NACE/ISO requirements where applicable, and approved manufacturer lists.
• Replacement parts: Match the original UNS grade unless an engineer approves the substitution.

Final recommendation

UNS S32750 and UNS S32760 are closely related super duplex stainless steel grades, but they are not the same material. UNS S32750 is the practical all-round 2507/F53 choice for many high-strength, chloride-resistant applications. UNS S32760 is the more specially alloyed F55/Zeron 100-type choice, distinguished mainly by copper and tungsten additions that can matter in aggressive chemical, alkali, seawater, and offshore environments.

If your drawing, code, or purchase order says UNS S32750, buy certified S32750. If it says UNS S32760, buy certified S32760. If the document only says “super duplex stainless steel,” clarify the required UNS number, product standard, corrosion environment, and welding requirements before ordering. That small step prevents the most common mistake in comparing uns32750 vs uns32760: treating two premium duplex steel grades as automatically interchangeable when the service conditions may say otherwise.