904L is an austenitic nickel-chromium stainless steel with molybdenum and copper additions. The elevated nickel and chromium content of 904L make it resistant to corrosion in a wide range of both oxidizing and reducing environments. The high nickel content also provides resistance to chloride stress corrosion cracking.

Molybdenum and copper are present in the alloy for increased resistance to pitting and crevice corrosion and to general corrosion in reducing acids.

The low carbon content of 904L provides resistance to intergranular corrosion in the post-welded or stress relieved condition.

Applications

The corrosion resistance of 904L makes it a useful alloy in numerous severe operating environments. It is utilized extensively in the chemical, petrochemical, pulp and paper, and pollution control industries :

• Tanks, vessels, piping, heat exchangers, and other equipment for the production and handling of sulfuric and phosphoric acid.
• Reactor vessels for fertilizer production
• Tall oil distillation
• Pulp and paper bleaching operations
• Absorber towers, stack linings, duct work, dampers, and other support equipment for flue gas desulphurization systems for fossil-fired power plants and waste incinerators.

Information provided by Carlson