904L (American Standard UNS N08904 / German Standard DIN 1.4539)
904L chemical properties:
904L mechanical properties:
8.0 g / cm3
904L solid solution state, mechanical properties of alloy at room temperature:
Tensile strength σb (Mpa)
Yield strength σ0.2 (Mpa)
This alloy has the following characteristics:
904L is a highly alloyed austenitic stainless steel with very low carbon content. The steel is designed for harsh environments. Because the 904L carbon content is very low (0.020% max), no carbides will be precipitated under general heat treatment and welding conditions. This eliminates the risk of intergranular corrosion that typically occurs after heat treatment and welding. Due to the high chromium-nickel-molybdenum content and the addition of copper, 904L can be passivated even in reducing environments such as sulfuric acid and formic acid. In pure sulfuric acid with a concentration range of 0 ~ 98%, the use temperature can reach 40 degrees Celsius. In pure phosphoric acid with a concentration range of 0 to 85%, its corrosion resistance is very good. In the industrial phosphoric acid produced by the wet process, impurities have a strong influence on the corrosion resistance. Among all kinds of phosphoric acid, 904L has better corrosion resistance than ordinary stainless steel. Among the highly oxidizing nitric acid, 904L has lower corrosion resistance compared to the highly alloyed steel grade that does not contain molybdenum. In hydrochloric acid, the use of 904L is limited to lower concentrations of 1-2%. In this concentration range, 904L steel has a high resistance to pitting corrosion. Its resistance to crevice corrosion is also good in chloride solutions. Due to the high nickel content, 904L has high resistance to stress corrosion cracking in chloride solution, concentrated hydroxide solution and hydrogen sulfide-rich environments
904L is a completely austenitic structure.
904L application range application fields are:
904L alloy is a versatile material that can be used in many industrial fields:
1. Petroleum, petrochemical equipment, such as reactors in petrochemical equipment, etc.
2. Storage and transportation equipment for sulfuric acid, such as heat exchangers
3. Power plant flue gas desulfurization device, the main use parts are: the tower body of the absorption tower, the flue, the door panel, the internal parts, the spray system, etc.
4. Scrubber and fan in organic acid treatment system
5. Seawater treatment equipment, seawater heat exchangers, paper industry equipment, sulfuric acid, nitric acid equipment, acid production, pharmaceutical industry and other chemical equipment
6. Dilute sulfuric acid strong corrosive medium 904L is the matching steel type
Varieties of products produced by our company:
Cold and hot plate, strip, wire, forged rod, hot rolled rod, machined product