The super duplex steel S32550 pipe is a high-quality, seamless pipe manufactured according to the ASTM A790 standards and has 24–27% chromium. Its balanced austenite-ferrite microstructure makes it stronger and more resistant to corrosion in harsh conditions.
ASTM A790 Super Duplex Steel UNS S32550 Seamless Pipe Manufacturer
We are Zhejiang Xintongda Special Steel (XTD), a reliable China-based manufacturer and a supplier of super duplex steel UNS S32550 seamless pipe. Alloy 255, also known as Ferralium 255, has a balanced austenite-ferrite microstructure. It contains 1.5% to 2.5% copper. Our pipes are produced through hot extrusion or cold drawing. This ensures dimensional accuracy, structural integrity, and compliance with the ASTM A790 standard. The copper addition offers better resistance to sulfuric and reducing acids than standard austenitic alloys like 316. We supply our products to various industries like chemical processing, marine engineering and seawater desalination for high-chloride process circuits. As a Multiple international certified company, we maintain the stock capacity of 25,000 tons annually, and we enforce an MOQ of 200 kg or none from stock. We deliver in-stock products in a week and new production orders in 15–60 days.
-
Standard
ASTM A790
-
OD Range
6-720 mm
-
Thickness
1-65 mm
-
Length
≤ 18 m
Get a free quote now
Technical Data
Technical Data
How to Make Super Duplex S32550 Seamless Pipes?
As one of the leading manufacturers of steel pipes in China, we make our Super Duplex S32550 seamless pipes using advanced processes as per the ASTM A790 standard. We begin by heating a billet. It is then formed through either hot extrusion or cold drawing during the production process. We heat-treat, pickle, and test all pipes for quality assurance. For more details, check how seamless pipes are made.
Key Features of ASTM A790 UNS S32550 Pipe
The properties of super duplex stainless steel S32550 provide it a combination of chemical stability and mechanical strength. We focus on these six main features:
- Resistance to Corrosion: The high chromium and copper content in Super Duplex S32550 creates a chemical balance that significantly improves corrosion resistance compared to standard austenitic grades. This makes it vital for chemical plants, where the copper addition creates a protective film that standard stainless steels lack.
- Low Thermal Expansion: S32550's low thermal expansion coefficient minimizes pipe movement during temperature cycling, protecting weld integrity in heat exchangers. This is a key advantage compared to high-expansion austenitic grades. The ferritic-austenitic structure maintains greater stability than single-phase steels during temperature fluctuations.
- Pitting and Crevice Corrosion: High molybdenum content prevents pit formation in chloride solutions, making S32550 ideal for stagnant seawater applications. It effectively prevents leaks in hidden gaps and under gaskets.
- Resistance to Stress Corrosion Cracking (SCC): The balanced duplex structure prevents cracking under high pressure in corrosive settings. Our pipes stop cracks from propagating, which ensures safety in oil and gas pipelines. This grade stands apart because it combines the strengths of both ferritic and austenitic steels to handle sour gas (H₂S-containing) environments.
- Erosion and Abrasion Resistance: The alloy's high hardness withstands wear from flowing sand or slurries, creating a durable barrier that lasts longer than standard stainless steel in mining pipes. This reduces the frequency of pipe replacements in systems carrying abrasive solids.
- Good Toughness and Ductility: S32550's balanced microstructure provides excellent impact absorption at low temperatures. This allows the pipe to bend and handle impact without the brittleness found in purely ferritic steels. The material stays strong and flexible even in freezing subsea conditions.
What are the Equivalent Grades of Super Duplex Steel S32550 Pipes?
UNS S32550 is internationally designated under several standards, such as DIN 1.4507 and EN 1.4507/X2CrNiMoCuN 25-6-3.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| 255 | S32550 | S25554 | 03Cr25Ni6Mo3Cu2N | SUS 329J4L | X2CrNiMoCuN25-6-3 | 1.4507 | - |
100% Certified Testing & Documentation
- EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
- Raw Materials Certificate
- 100% PMI
- Heat Treatment Charts
- Third-Party Inspection Report
- Surface roughness and size measurement
- Manufacturer Test Certificate (Impact Testing, Flattening, Flare, Bend, Hardness, Intergranular, Pitting Corrosion, Grain size, ET, UT, HT)
- Laboratory Test Certificate from the Government-Approved Lab
Which Industries Use Super Duplex S32550 Pipes?
S32550 super duplex stainless steel seamless pipes serve demanding applications across five major industries. These include:
Chemical Processing
Chemical processing plants use S32550 pipe to transport hot sulfuric, phosphoric, and nitric acids. The alloy prevents rapid thinning in acidic reactors and piping manifolds handling high-concentration acids.
Marine Engineering
Marine engineers use our S32550 pipes for subsea piping systems and seawater handling equipment. The alloy can withstand repeated exposure to salt sprays and high-velocity seawater with high resistance to degradation.
Seawater Desalination Plants
We provide this pipe for seawater desalination plants, including high-pressure reverse osmosis units and brine heaters. This pipe resists the concentrated brine that typically causes pitting in 316L stainless steel.
Oil and Gas Industry
Our UNS S32550 pipe is widely used in oil and gas industry operations for downhole tubing, flowlines, and subsea umbilicals. It handles sour gas and high-pressure environments without the risk of stress cracking.
Paper Industry
Paper industry equipment, such as bleach washers and liquor tanks, requires this grade for longevity. It reduces corrosion issues caused by the recycling process of liquids in closed-loop systems.
Frequently Asked Questions
-
What is super duplex steel S32550 pipe?
-
Why choose super duplex S32550 pipes for industrial use?Choose Super Duplex S32550 pipes for two to three times the yield strength of 304/316 austenitic grades, plus a Critical Pitting Temperature (CPT) typically in the range of 38–50°C. It works well with acids and chlorides, and costs less than pricier super duplex grades.
-
What is the difference between the S32550 pipe and the S32750/S32760 pipe?The difference between the S32550 pipe and the S32750/S32760 pipe is that S32550 has a similar chromium range (24–27%) to S32750/S32760 (24–26%), but less molybdenum and nitrogen. This makes it less resistant to pitting and crevice corrosion. The addition of 1.5 to 2.5% copper, on the other hand, improves performance in acidic environments. This makes it a more cost-effective option for mildly corrosive conditions.