Stancor Tubulars
Austenitic Stainless SteelUNS N08904W.Nr 1.4539

Stainless Steel 904L Seamless Pipes & Tubes

SS 904L (UNS N08904) is a high-alloy austenitic stainless steel with elevated nickel (25%), molybdenum (4.5%), and copper content. It provides exceptional corrosion resistance in sulfuric acid, phosphoric acid, and chloride-containing environments, bridging the gap between standard stainless steels and nickel alloys.

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Size Range

1/4" NPS to 10" NPS (6.35mm to 273.1mm OD)

Wall Thickness

SCH 5S to SCH 80S

Standards

4 specs

Chemical Composition (% by weight)

C0.020 max
Mn2.00 max
Si1.00 max
Cr19.0-23.0
Ni23.0-28.0
Mo4.0-5.0
Cu1.0-2.0
P0.045 max
S0.035 max

Mechanical Properties (Minimum at Room Temperature)

Tensile Strength490 MPa min
Yield Strength220 MPa min
Elongation35% min
Hardness90 HRB max

Physical Properties - SS 904L

Density7.95 g/cm3
Melting Range1350-1400 C
Thermal Conductivity12.2 W/m-K
Electrical Resistivity950 nOhm-m
Specific Heat460 J/kg-K
Coeff. of Thermal Expansion15.8 um/m-C

Corrosion Resistance - SS 904L

PropertyValue
Pitting Resistance (PREN)~36
Max Service Temp (Oxidizing)450 C
Intergranular CorrosionHighly resistant
Stress Corrosion CrackingExcellent resistance
General Corrosion Rate<0.01 mm/yr in dilute sulfuric acid
Seawater ResistanceExcellent

Equivalent International Grades

ASTMN08904
JISSUS 890L
TradeUranus B6

SS 904L vs Comparable Grades

GradeTensileYield
SS 317LAustenitic Stainless Steel515 MPa min205 MPa min
SS 316 / 316LAustenitic Stainless Steel515 / 485 MPa min205 / 170 MPa min
Alloy 825Nickel-Iron-Chromium-Molybdenum Alloy586 MPa min241 MPa min
VS
SS 904L vs SS 317L: 904L has higher alloy content for more aggressive acids; costs more.
VS
SS 904L vs SS 316 / 316L: 904L far superior in acids and chlorides; 316 for mild environments.
VS
SS 904L vs Alloy 825: 825 has similar performance; 904L better in sulfuric acid, 825 better in reducing acids.

Applicable Standards

ASTM A312 / ASME SA312ASTM B673 / ASME SB673ASTM B674 / ASME SB674DIN EN 10216-5

Applications

Sulfuric acid handling and storage
Phosphoric acid production
Seawater cooling systems
Bleaching equipment in pulp mills
Organic acid processing
Gas scrubbing systems

Key Advantages of SS 904L

Exceptional sulfuric acid corrosion resistance
Outstanding pitting resistance (PREN ~36)
Copper addition improves resistance to reducing acids
Excellent SCC resistance due to high nickel content
More economical than nickel alloys for many acid applications

SS 904L Applications by Region

🇬🇧

Middle East (UAE, Saudi Arabia, Qatar, Oman, Kuwait)

Specified for acid handling systems, seawater applications, and petrochemical plants in UAE, Saudi Arabia, and Qatar.

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Europe (Germany, UK, Norway, Netherlands, Italy)

Standard for fertilizer plants, chemical processing, and marine applications in Germany, Netherlands, and Scandinavia.

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United States

Used in chemical processing, fertilizer production, and marine applications.

Frequently Asked Questions about SS 904L Seamless Pipes

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