C: ≤ 0.020 – Mn: ≤2.00 – Si: ≤ 0.70 – Cr: 19.00÷21.00 – Ni: 24.00÷26.00 – Mo: 4.00÷5.00 – N: ≤ 0.15 – Cu: 1.2÷2.0 – S: ≤ 0.010 – P: ≤0.030
EN: X1NiCrMoCu25-20-5 – W.N.: 1.4539 AISI: AISI 904L
Austenitic stainless steel characterized by good corrosion resistance in high corrosive environments, called also “superaustenitic”.
It’s the last chance against corrosion problems before using nickel or cobalt alloys.
Its low “C” content , and the high “Mo” “Cr” content endow it with excellent resistance to corrosion even in the presence of chlorine ions. The Ni content of 24¸26% with the addition of copper gives them good strength against stress-corrosion conditions, also in presence of sulphur. This grade is largely used in paper mills, in desulphurization plants, and in chemical industry to synthetise phosphoric and sulphuric acid, and fertilizers.
904L stainless steel combines molybdenum and copper with iron for tremendously increased resistance to reducing acids like sulphuric acid. It stands up extremely well to chlorides in the environment for low pitting and crevice corrosion, as well as stress corrosion cracking.
Grade 904L stainless steel is one of many stainless steel grades that can be purchased at yaang.com.
The “L” in 904L stands for Low Carbon, specifically, that carbon added to the alloy represents .03 percent or less. This means that 904L has very good welding properties. It is also an austenitic alloy, which means that a nonmagnetic solid solution of ferric carbide or carbon in iron is used to increase corrosion resistance.
Properties and Uses of 904L Stainless Steel
904L Stainless Steel cannot be hardened by heat treatment. You can weld 904L stainless using any standard method, but it is susceptible to hot cracking. It can be machined but does not machine well.
Common applications take advantage of 904L’s corrosion resistance. These include acid processing plants, pulp and paper operations, equipment for cooling seawater, oil refining, and environmental equipment.
Source: Yaang Pipe Industry (www.yaang.com)