904L Stainless Steel Sheet

UNS NO8904, commonly known as 904L, is a low carbon high alloy austenitic stainless steel which is widely used in applications where the corrosion properties of AISI 316L and AISI 317L are not adequate.

The addition of copper to this grade gives it corrosion resistant properties superior to the conventional chrome nickel stainless steels, in particular to sulphuric, phosphoric and acetic acids. However, there is limited use with hydrochloric acids. It also has a high resistance to pitting in chloride solutions, a high resistance to both crevice and stress corrosion cracking. Alloy 904L performs better than other austenitic stainless steels due to the higher alloying of nickel and molybdenum.

Chemical composition(%)
 
Carbon       0.02% max 
Chromium   19.00-23.00%
Manganese  2.00% max 
Nickel         23.00-28.00%
Silicon       1.00% max 
Molybdenum   4.00-5.00%
Phosphorous  0.045% max 
Copper          1.00-2.00%
Sulphur          0.035% max

Corrosion Resistance 
Where a level of resistance to pitting corrosion better than 316 is required 904L may be suitable. With its high nickel content at 25% it offers improved resistance to chloride stress corrosion cracking compared to other austenitic grades such as 304.

Welding 
904L can be welded using common fusion and resistance methods. A more highly alloyed filler is recommended to give the optimum corrosion properties in the weld. We recommend you contact your welding consumables supplier who should provide you full assistance and information on welding 904L stainless steel.

Typical Applications

Seawater cooling equipment
Chemical processing for sulphuric, phosphoric and acetic acids
Gas washing
Condenser tubes
Control and instrumentation
Heat exchangers

Industries predominantly using this grade           
Chemical processing
Oil and gas
Pharmaceutical