6.0mm 8.0mm 12.0mm UNS N08904 904L Stainless Steel Plate 904L Plate TISCO SS904L Plate

904L is an austenitic 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. The high nickel (25%) and molybdenum (4.5%) contents of 904L provide good resistance to chloride stress corrosion cracking, general and chloride pitting corrosion resistance above the levels of 316 and 317 stainless. The copper addition provides added resistance to hot phosphoric acid and dilute sulfuric acid.

Inventory

904L Weld Wire

Common Trade Names

Specifications

Features

Critical Crevice Corrosion Temperature*

* ASTM procedure G-48, 10% ferric chloric solution

• Tubesheets
• Acid and fertilizer production
• Utility scrubbers
• Pickling equipment

Related Literature

• Data Sheet
• AL-6XN vs 904L
• Alloy 20 vs AL-6XN/904L

Grade 904L:

• Austenitic stainless steel sheet of Grade 904L is a non-stabilized, high alloy, low carbon steel. With the inclusion of copper, this grade is significantly more resistant to strong reducing acids, particularly sulfuric acid. Moreover, it offers robust defense against chloride-induced stress corrosion cracking and pitting/crevice corrosion.
• This grade boasts outstanding formability and weldability and is non-magnetic under all conditions. Its austenitic structure provides exceptional toughness, even at cryogenic temperatures.
• 904L stainless steel, enriched with substantial amounts of nickel and molybdenum, is known for its premium quality and high cost. While it has traditionally excelled in various applications, the emergence of Duplex stainless steel 2205 (S31803 or S32205) offers a cost-efficient alternative, thereby reducing the frequency of 904L's usage in contemporary industries.

Corrosion Resistance:

• 904L stainless steel boasts exceptional resilience across a multitude of conditions, originally developed to resist sulfuric acid. Its robust performance extends to warm seawater and high-chloride environments, supported by a PRE of 35. The high nickel content ensures superior resistance to stress corrosion cracking compared to typical austenitic grades. Copper bolsters resistance to sulfuric and other reducing acids, especially in the highly aggressive 'mid concentration' range.
• 904L offers corrosion resistance that is generally intermediate between standard austenitic grade 316L and highly alloyed 'super austenitic' grades containing 6% molybdenum and similar contents.
• When compared to molybdenum-free grades like 304L and 310L, 904L offers lesser resistance to some aggressive conditions.
• For optimal resistance to stress corrosion cracking in demanding environments, it is recommended to solution treat the steel after cold working.

Heat Resistance:

• 904L features robust oxidation resistance; however, it may develop structural instability at higher temperatures due to the precipitation of brittle phases such as sigma. It is not advisable to use 904L above 550°C. According to the ASME Boiler and Pressure Vessel Code, the design stress values for 904L are specified at 371°C.

Heat Treatment:

• Solution Treatment (Annealing): Heat to 1090-1175°C and cool rapidly. This grade cannot be hardened through thermal treatment.

Welding:

• 904L can be successfully welded using all standard techniques. Due to its fully austenitic solidification, caution is necessary to avoid heat cracking, especially in constrained weldments. Pre-heat is not recommended, and post-weld heat treatment is generally unnecessary. 904L welding rods and electrodes are prequalified by AS 1554.6.

Fabrication:

• 904L, being a high purity, low *** grade, does not machine as easily as other grades designed specifically for machinability. However, it can still be machined using conventional methods. Bending to a small radius is straightforward and typically performed cold. While subsequent annealing is generally unnecessary, it should be considered if the fabricated component is to be used in environments prone to severe stress corrosion cracking.

Typical Applications:

• 904L stainless steel is ideal for processing plants handling sulfuric, phosphoric, and acetic acids. It is also used in pulp and paper processing, gas scrubbing plant components, seawater cooling equipment, oil refinery components, and wires in electrostatic precipitators.

Specified Properties:

• Under ASTM A240M, the specified properties are mandatory for flat-rolled products such as plates, sheets, and coils. Similar properties apply to other products like pipes, tubes, and bars, although slight variations may exist based on individual specifications.

904L Stainless Steel Sheets in a Variety of Finishes

Our 904L stainless steel sheets are available in a range of exquisite finishes including brushed finish, 2B smooth finish, and 8K mirror finish.

Each stainless steel sheet we supply has a finished side coated with a protective film, which is easily removed after fabrication or installation, ensuring the surface remains pristine. The back side of the sheet remains unfinished.