URANUS® B6 – 904L1.4539 – N08904 – X1NiCrMoCuN 25 20 5

904L® alloy (UNS N08904) is an austenitic stainless steel alloy designed for a middle to high level of corrosion resistance. The alloy contains high levels of chromium and nickel with additions of molybdenum and copper to provide added corrosion resistance in certain media. The alloy is produced to low carbon levels for use in the welded condition as in welded vessels and other large and complex fabrications.The high nickel (25%) and molybdenum (4% – 5%)contents of the 904L® alloy provide good resistance to chloride stress corrosion cracking. Chromium, molybdenum and nickel levels provide a level of general and chloride pitting corrosion resistance above the level of Types 316 and 317 in many media. The copper addition at this alloy content provides added resistance to reducing media such as hot phosphoric acid and dilute sulfuric acid. The N08904 alloy has been incorporated in ASTM and ASME specifications, and is widely and readily available in a variety of product forms, weldingelectrodes, and fittings. The Alloy 904L® alloy has performed well in a variety of service environments such as utility scrubbers, acid and fertilizer production.

ACEQUISA 904 N08904 1.4539 EN


URANUS® B6 – 904L
seamless-pipe Seamless Tubes

welded-pipe Welded Tubes  stock
plate Plates  stock
bar Bars  stock
flanges Flanges  stock
accessories Fittings  stock


  • Processing plant for sulphuric, phosphoric and acetic acids
  • Pulp and paper processing
  • Components in gas scrubbing plants
  • Seawater cooling equipment
  • Oil refinery components
  • Wires in electrostatic precipitators

General characteristics

  • High strength and hardness
  • Excellent corrosion resistance
  • Good resistance to impingement attack
  • High fatigue strength in seawater
  • Low magnetic permeability

Technical information



904L® – UNS N08904
Seamless Tubes A-269 B-677
Welded Tubes A-269 B-674
Plates B-625
Bars B-625
Flanges A-182 B-649
Fittings B-366

Chemical specifications %


904L® – UNS N08904
Element Simbol Maximum %
Carbon C 0,020
Manganese Mn 2,00
Phosphorus P 0,045
Sulfur S 0,035
Silicon Si 1,00
Nickel Ni 23,0-28,0
Chrome Cr 19,0-23,0
Molybdenum Mo 4,0-5,0
Copper Cu 1,0-2,0
Iron Fe Balance

Mechanical Properties

904L® – UNS N08904
Norm Rm min. Rp 0,2% min E4d min.% Z min.% T.I (J) HR B HB
A-182 71 (490) 31 (215) 35
B-625 71 (490) 31 (220) 35 70 – 90
B-649 71 (490) 31 (220) 35
B-673 71 (490) 31 (220) 35
B-674 71 (490) 31 (220) 35
B-677 71 (490) 31 (220) 35