904L (N08904,14539) Super Austenitic Stainless Steel is a low-carbon, high-alloy austenitic stainless steel containing 140-18.0% chromium, 240-26.0% nickel and 45% molybdenum. The material is manufactured using the know-how of the French company H·S and has excellent activation-passivation transition and corrosion resistance. It exhibits good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, while it also has excellent resistance to pitting and crevice corrosion in neutral chloride-containing media. In various concentrations of sulfuric acid, 904L stainless steel can be used at temperatures up to 70 degrees Celsius. It also has very good corrosion resistance in acetic acid and mixed acids of various concentrations. 
The metallographic structure of this super austenitic stainless steel is completely austenitic and insensitive to the precipitation of ferrite and phase. Due to its high chromium, nickel and copper content, it can also be passivated in reducing environments such as sulphuric acid and formic acid. In sulfuric acid and phosphoric acid, it has excellent corrosion resistance and maintains stable performance even in very harsh environments. 
The physical and mechanical properties of 904L stainless steel are also excellent. It has a density of 80g cm, tensile strength 520MPa, elongation 35%. These properties allow it to withstand high levels of pressure and tensile forces, while also providing good machinability and weldability. 
In terms of applications, 904L stainless steel is widely used in various fields that need to withstand highly corrosive environments, such as chemical reactors, storage tanks, pipelines, etc. It is also an ideal material for the manufacture of critical equipment such as pressure vessels.