🟧 Product Overview
Super austenitic stainless steels 904L and 254SMO are designed for extremely corrosive environments, especially those containing high chloride concentrations, seawater, acidic media, and halide chemicals.
904L Stainless Steel Pipe
High nickel (23–28%) + molybdenum (4–5%)
Excellent resistance to sulfuric acid, phosphoric acid, and chloride pitting
Non‑stabilized low‑carbon grade → excellent weldability
254SMO Stainless Steel Pipe
Super austenitic stainless steel with 6–6.5% Mo + 0.18–0.22% N
PREN ≥ 42 → comparable to duplex 2507 in pitting resistance
Designed for seawater, offshore, desalination, and extreme chloride environments
Key Advantages:
Exceptional resistance to pitting, crevice corrosion, and chloride stress corrosion cracking
High strength and toughness
Excellent weldability (especially 904L)
Suitable for the harshest industrial and marine environments
🟧 Standards
ASTM A312 / A312M
ASTM B677 (904L)
EN 10216‑5
NACE MR0175 / ISO 15156
GB/T 14976
🟧 Grades
904L (UNS N08904) 254SMO (UNS S31254 / EN 1.4547)
🟧 Product Specifications & Available Sizes
Outer Diameter (OD)
Seamless: 6–530 mm
Welded: 12–630 mm
Wall Thickness (WT) Length Type
Seamless (Cold Drawn / Hot Rolled)
Welded (ERW / TIG / Laser Welded)
Surface Finish Options
Pickled
Annealed
Polished (180–400 grit)
High‑corrosion‑resistant finish
🟧 Chemical Composition
（ASTM）
904L Element Content (%) C ≤ 0.02 Si ≤ 1.00 Mn ≤ 2.00 P ≤ 0.045 S ≤ 0.035 Cr 19.0–23.0 Ni 23.0–28.0 Mo 4.0–5.0 Cu 1.0–2.0 N ≤ 0.10
254SMO Element Content (%) C ≤ 0.02 Si ≤ 0.80 Mn ≤ 1.00 P ≤ 0.030 S ≤ 0.010 Cr 19.5–20.5 Ni 17.5–18.5 Mo 6.0–6.5 N 0.18–0.22
🟧 Mechanical Properties
904L Property Requirement Tensile Strength ≥ 490 MPa Yield Strength ≥ 220 MPa Elongation ≥ 35%
254SMO Property Requirement Tensile Strength ≥ 650 MPa Yield Strength ≥ 300 MPa Elongation ≥ 35%
🟧 Physical Properties
Property 904L 254SMO Density 8.0 g/cm³ 8.0 g/cm³ Melting Point 1350–1400°C 1320–1390°C PREN ~35 ≥ 42 Thermal Conductivity 12.5 W/m·K 12.0 W/m·K
🟧 Manufacturing Processes
Hot Rolling
Cold Drawing
TIG Welding
Laser Welding
Solution Annealing
Pickling
Polishing
Hydrostatic Testing
Eddy Current Testing
🟧 Primary Industry Usage
Offshore platforms
Seawater cooling systems
Desalination plants
Chemical & petrochemical processing
Pulp & paper bleaching equipment
Acid handling systems
High‑chloride industrial environments
🟧 Why Use 904L / 254SMO Stainless Steel Pipe
Exceptional resistance to chloride‑induced corrosion
Superior pitting & crevice corrosion resistance
High strength and durability in harsh environments
Suitable for seawater and aggressive chemical media
254SMO offers performance comparable to super duplex grades
🟧 Why Choose WelSteels
Full supply range of super austenitic stainless steels
Strict quality control with MTC 3.1
Expertise in offshore, marine, and chemical applications
Seamless & welded options for both 904L and 254SMO
Global shipping with professional loading supervision
Competitive pricing for high‑alloy stainless steel projects
