Stainless Steel 904 / 904L
Common Trade Names: Alloy 904L , N08904 , W.Nr 1.4539 , N08904 , Cr20Ni25Mo4.5Cu
904L is a Super Austenstic Stainless Steel with low carbon content. The grade is intended for use under severe corrosive conditions. It has been application proved over many years and was originally developed to resist corrosion in dilute sulfuric acid. It is standardized and approved for pressure vessel use in several countries. Structurally, 904L is fully austenitic and is less sensitive to precipitation ferrite and sigma phases than conventional austenitic grades with high molybdenum content. Characteristically, due to the combination of relatively high contents of chromium, nickel, molybdenum and copper 904L has good resistance to general corrosion, particularly in sulfuric and phosphoric conditions.
| C | Cr | Ni | Mo | Si | Mn | P | S | Cu | N |
| ≤0.02 | 19.0-23.0 | 23.0-28.0 | 4.0-5.0 | ≤1.0 | ≤2.0 | ≤0.045 | ≤0.035 | 1.0-2.0 | ≤1.0 |
| Density （g/cm3） |
Melting point (℃) |
Elastic modulus (GPa) |
Thermal expansion coefficient (10-6℃-1) |
Thermal conductivity (W/m℃) |
Electric resistivity (μΩm) |
| 8.0 | 1300-1390 | 195 | 15.8 | 12 | 1.0 |
| Temperature （℃） |
бb（N/mm2） | б0.2（N/mm2） | δ5（%） | HRB |
| Room temperature | ≤490 | ≤220 | ≥35 | ≤90 |
Alloy 904L Standards and Specifications
ASME SB-625, ASME SB-649, ASME SB-673, ASME SB-674, ASME SB-677
Alloy 904L Available Products in Sekonic Metals
Alloy 904L Bars & Rods
Round bars/Flat bars/Hex bars, Size From 8.0mm-320mm, Used for bolts,fastners and other spare parts
Alloy 904L Wire
Supply in welding wire and spring wire in coil form and cut length.
Alloy 904L sheet & plate
Widths up to 1500mm and lengths up to 6000mm,Thickness from 0.1mm to 100mm.
Alloy 904L seamless tube & Welded pipe
Standards size and customized dimension can be produced by us with small tolerance
Alloy 904L strip & coil
Soft condition and hard condition with AB bright surface, width up to 1000mm
Alloy 904L Fasteners
Alloy 904L materials in forms of Bolts,screws,flanges and other fasterners, according to clients specification.
Why Alloy 904L ?
• Good resistance to pitting corrosion and crevice corrosion
• High resistance to stress corrosion cracking, intergranular, good machinability and weldability
• In all the various kinds of phosphates904L alloy corrosion resistance is superior to the ordinary stainless steel.
• In strong oxidizing nitric acid, compared to high alloy without molybdenum steel grade, 904Lshows lower corrosion resistance.
• This alloy has better corrosion resistance than the conventional stainless steel .
• Reduce the corrosion rate of the pit and gaps for the high content of nickel, and have good resistance to stress corrosion cracking, in the environment of chloride solution, concentration of hydroxide solution and rich hydrogen sulphide.
Alloy 904L Application field：
• Petroleum and petrochemical equipment，such as reactor of petrochemical equipment, etc.
• Sulfuric acid storage and transportation equipment, such as heat exchangers, etc.
• Power plant flue gas desulfurization devicen,Main parts of use:the absorber tower body, flue,internal parts, spray system, etc
• Organic acid scrubber and the fan in the processing system.
• Water treatment plant, water heat exchanger, papermaking equipment,sulfuric acid, nitric acid equipment, acid,
• Pharmaceutical industry and other chemical equipment, pressure vessel, food equipment.
• Pharmaceutical: centrifuge, reactor, etc.
• Plant foods: soy sauce pot, cooking wine, salt, equipment and dressings.
• To dilute sulphuric acid strong corrosive medium steel 904 l is matching.
