CORROSION RESISTANCE :

In sulfuric acid environments, the range of concentrations and temperatures in which UR™ 904L can be used is much wider than the one of most of the other high corrosion resistant grades
(such as UR™ 317L and UR™ 2205).
This is partially explained by high content of nickel, chromium, molybdenum and also its copper addition.
General corrosion resistance properties of alloy UR™ 904L in industrial phosphoric acid solutions is excellent and much better than the one of the austenitic grades 316L and 317L. At higher temperatures, the alloy behaves also better that the duplex grade UR™ 2205.
UR™ 904L is today commonly used for phosphoric acid applications. The corrosion resistance in this environment is strongly influenced by the presence of impurities (chlorides, fluorides, ...).
The high chromium and molybdenum contents of UR™ 904L make its resistance to pitting and crevice corrosion superior to 316L and 317L.
The very low carbon content of UR™ 904L makes this alloy resistant to intergranular corrosion. Due to its high nickel and molybdenum content, UR™ 904L is more resistant to stress corrosion cracking than other standard austenitic materials.
Field experience and laboratory tests show that UR™ 904L performs much better than 304L and 316L grades. This is particularly true in high temperature chloride containing solutions where early failures are often reported for 304L and 316L. 

APPLICATIONS :

• Phosphoric acid, fertilizers, phosphate industries,
• Sulphuric acid solutions and hydrometallurgy,
• Saline solutions and, with some restrictions, seawater applications,
• Sour gas applications (separators...),
• Pollution control equipments,
• Chemical plants (medium to severe conditions)