UNS N08904 Super Austenstic Stainless Steel(1.4539,904L)

UNS N08904 is a high-alloy austenitic stainless steel with high molybdenum and low carbon content,also known as 904L falls in the austenitic stainless steel group. Copper content in the alloy greatly improves resistance to strong reducing acids, especially (H2SO4) sulphuric acid. 904L has better resistance ti chloride attack against both stress corrosion cracking and crevice / pitting corrosion .
With excellent weldability and formability 904L also maintain non-magnetic state in all conditions.904Lprovides excellent toughness, even down to cryogenic temperatures with its austenitic structure.
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.

Chemical Composition:
C　　　　 Cr　　　　 Cu　　 Mn　　 Mo　　　 Ni 　　　　P 　　　S 　　Si
0.02　 19.0-23.0　 1.0-2.0 　2.0 　4.0-5.0 　23.0-28.0　 0.045　 0.035　 1.0

Specifications:
Standard 904L　　　 　　　　UNS N08904
Werkstoff Nr. 1.4539　　　 Density 8.05 g/cm3

Typical Applications:
Production and transport of sulfuric acid
Metal pickling in sulfuric acid
Production and concentration of phosphoric acid
Use in seawater, brackish water, condensers, heat exchangers and pipe work in general
Paper and allied industries
Gas washing
Chemical and pharmaceutical industries