Super austenitic stainless steel (904L / 254SMO) has high corrosion resistance, strong acid resistance, pitting corrosion resistance, and stress corrosion resistance, and is used in high-end chemical, nuclear power, seawater, desulfurization, and precision equipment.
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Name |
Super Austenitic Stainless Steel Coil |
|
Grade |
904L, 254SMO (S31254), AL-6XN (N08367), 654SMO (S32654), etc. |
|
Standard |
ASTM, ASME, EN, UNS, JIS, etc. |
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Thickness |
0.3mm–10.0mm (cold rolled), 6mm–100mm (hot rolled) |
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Width range |
1000mm, 1219mm, 1250mm, 1500mm, customized |
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Length |
Customized |
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Size |
10002000mm, 12192438mm, 1219*3048mm, customized Max. width 2000mm |
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Finish |
2B, BA, No.4, 8K, Brushed, Hairline, Pickling & Passivation |
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Color |
Silver (standard), PVD Coating (customized: Golden, Black, Rose gold, etc.) |
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Application |
Chemical processing equipment, seawater desalination, FGD systems, oil & gas pipelines, pharmaceutical equipment, food processing machinery, high-corrosion industrial components |
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Lead time |
15 to 35 working days after the receipt of 30% deposit |
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Payment terms |
30% TT for deposit, 70% balance before shipment or LC at sight |
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Packing |
Waterproof paper + steel strip + wooden pallet or according to customer’s request |
Metallographic structure: Austenitic + Ferritic ≈ 1:1
Inherently combines: High strength + Strong corrosion resistance + Good toughness
**Most typical examples:** 2205, 2507 Duplex steel = High-end stainless steel with double the strength, stronger corrosion resistance, greater durability, and lower cost.
Ⅱ.Core Differences Between Duplex Stainless Steel and Ordinary Stainless Steel (304 / 316L)
304/316L: Yield Strength ≈ 200MPa
Duplex Stainless Steel (2205): Yield Strength ≥ 450MPa → More than twice the strength of ordinary stainless steel → Can be made thinner, lighter, and lower cost
304: Sensitive to seawater and chloride ions
316L: Resistant to general corrosion, but moderately resistant to pitting/crevice corrosion
Duplex Stainless Steel: Particularly resistant to seawater, chloride ions, and stress corrosion → Suitable for coastal, chemical, desalination, shipbuilding, and oil and gas projects
More expensive than 304
Slightly more expensive than or close to 316L
However, considering overall lifespan, thickness, and maintenance costs → Cost-effectiveness is far superior to 316L
304: Decorative, kitchenware, general equipment
316L: Chemical, coastal, moderate corrosion
Duplex Stainless Steel: Seawater, oil and gas, high corrosion, high pressure, heavy structures
Based on alloy content and performance, the industry generally classifies duplex steel into 4 categories:
Representatives: 2101, 2304
Features: Inexpensive, a substitute for 316L
Corrosion resistance ≈ 316L, higher strength
Representative: 2205 (Most mainstream, highest sales volume)
90% of duplex steel exported is this
Strong corrosion resistance, high strength, and the most versatile
Representative: 2507
High Cr, high Mo, high N
Extremely resistant to corrosion: seawater, oil and gas, strong acids, high-pressure conditions
Representatives: 32707, etc.
Extreme conditions: deep sea, high temperature, high chlorine, strong corrosion
Low usage, high price
- International Grade: UNS S32205 / S31803, corresponding to Chinese National Standard 022Cr22Ni5Mo3N
- Microstructure: Austenitic + Ferritic duplex structure (ratio approximately 1:1), possessing excellent properties of both phases
- Standards: ASTM A240/A276/SA-182, covering the full range of plates/pipes/bars
- International Grade: UNS S32750, corresponding to Chinese National Standard 022Cr25Ni7Mo4N, also known as SAF 2507
- Microstructure: High-alloy duplex structure, significantly improved chromium, molybdenum, and nitrogen content, achieving top corrosion resistance among duplex steels
- Standards: ASTM A790/A479, mainstream certification in high-end marine engineering and chemical industries
Key performance parameters
|
Performance Dimension |
2205 (S32205) |
2507 (S32750) |
Advantage over 316L |
|
Yield Strength |
≥ 450 MPa (2x that of 304/316L) |
≥ 550 MPa (up to 800 MPa) |
Double the strength, allowing 30%-50% wall thickness reduction |
|
Tensile Strength |
≥ 620 MPa |
≥ 800 MPa (up to 1000 MPa) |
High load-bearing capacity, suitable for high-pressure working conditions |
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Elongation |
≥ 25% |
≥ 20% |
Excellent toughness, impact-resistant without brittle fracture |
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Corrosion Resistance |
PREN 32-38, resistant to chloride pitting/crevice corrosion |
PREN ≥ 42, resistant to high chloride/strong acid/hydrogen sulfide |
Critical pitting temperature >75°C, service life extended by 3 times |
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Operating Temperature |
-50°C to 250°C (long-term ≤250°C) |
-50°C to 315°C |
Wide temperature range adaptability, stable at high and low temperatures |
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Weldability |
Good, requires control of heat input to avoid σ-phase precipitation |
Good, requires matching special welding materials, interpass temp ≤100°C |
Adaptable to mass production, reduces construction/processing costs |
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Element
|
C ≤ |
Si ≤ |
Mn ≤ |
P ≤ |
S ≤ |
Cr |
Ni |
Mo |
N |
|
Range |
0.03 |
1.00 |
2.00 |
0.030 |
0.020 |
21.0-24.0 |
4.5-6.5 |
2.5-3.5 |
0.08-0.20 |
|
Element
|
C ≤ |
Si ≤ |
Mn ≤ |
P ≤ |
S ≤ |
Cr |
Ni |
Mo |
N |
|
Range |
0.03 |
0.80 |
1.20 |
0.035 |
0.020 |
24.0-26.0 |
6.0-8.0 |
3.0-5.0 |
0.24-0.32 |
Mainstream product forms
|
Product Form |
2205 Core Specifications |
2507 Core Specifications |
Application Scenarios |
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Plate/Sheet |
3.0-100mm × 1500-4000mm, 2B/NO.1 surface |
4.0-80mm × 1500-3600mm, pickled/drawn |
Chemical storage tanks, desulfurization towers, ship plates |
|
Pipe/Tubing |
Seamless pipe Φ 10-630mm × 1.5-50mm |
Seamless pipe Φ 15-500mm × 2.0-40mm |
Seawater transportation, oil & gas pipelines, RO equipment |
|
Bar/Rod |
Φ 10-200mm, hot rolled/cold drawn |
Φ 12-180mm, forged/hot rolled |
Pump & valve components, shafts, fasteners |
|
Pipe Fittings |
Elbows/tees/flanges, ASME B16.5 |
High-pressure pipe fittings, adapted for ultra-high pressure conditions |
Pipeline system accessories |
Duplex stainless steel coils are renowned for their exceptional corrosion resistance and high mechanical strength, and are widely used in offshore engineering, seawater desalination, oil and gas pipelines, and harsh industrial environments. Unlike ordinary steel, they possess excellent resistance to chloride stress corrosion, pitting corrosion, and crevice corrosion. However, their performance may be limited in extremely high-temperature or highly oxidizing acidic conditions. Duplex stainless steel is available in various grades and surface treatments to suit different harsh operating conditions.
Duplex stainless steel coils use 2205, 2507, and 2304 duplex stainless steel sheets as raw materials to ensure superior quality of the finished product. The steel sheets undergo surface treatment through chemical and mechanical methods such as pickling, passivation, and polishing to improve corrosion resistance and surface finish. Subsequently, the treated steel sheets are cold-rolled using a cold rolling mill to ensure that their thickness and dimensional accuracy meet requirements. Finally, the cold-rolled stainless steel strips are slit into strips and coiled to produce duplex stainless steel coils. The finished coils are properly packaged for easy storage and transportation.
In order to ensure product quality, we will arrange professional personnel to check product quality, packaging, weight, hardness, etc., according to customer requirements of product specifications, looking for high-quality and cheap cooperative factories in China, to provide customers with one-stop procurement services and quality assurance.
Excellent packaging: waterproof paper and plastic film + iron cover + at least three strapping straps + strapping straps fixed on iron or wood pallets can effectively protect products from corrosion and various climate changes during transportation. Generally speaking, we ship from Shanghai, Tianjin, Qingdao and Ningbo ports. We have worked with many experienced shipping companies for a long time to find the most suitable mode of transportation for you.
