1.4539 super austenitic stainless steel grades, characteristics and uses

1.4539 super austenitic stainless steel grades, characteristics, and uses
1.4539 material grades: 1.4539 super austenitic stainless steel, American grade: UNS N08904, Swedish grade: 904L, Chinese grade: 00Cr20Ni25Mo4.5Cu;
1.4539 super austenitic stainless steel overview: 1.4539 super austenitic stainless steel contains 14.0-18.0% chromium, 24.0-26.0% nickel, and 4.5% molybdenum. 904L super austenitic stainless steel is a low-carbon, high-nickel, molybdenum austenitic stainless acid-resistant steel, which is a proprietary material introduced from the French H·S company. It has good activation-passivation transformation ability, excellent corrosion resistance, good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, good pitting resistance in neutral chloride ion media, and good crevice corrosion resistance and stress corrosion resistance. It is suitable for various concentrations of sulfuric acid below 70℃, and has good corrosion resistance in acetic
acid of any concentration and any temperature under normal pressure, as well as in the mixed acid of formic acid and acetic acid. Super austenitic stainless steel 1.4539 is a high-alloy austenitic stainless steel with low carbon content. It has good corrosion resistance in dilute sulfuric acid and is designed for environments with harsh corrosive conditions. It has a high chromium content and sufficient nickel content. The addition of copper makes it very acid-resistant, especially highly resistant to chloride crevice corrosion and stress corrosion cracking. It is not easy to have pitting and cracks. Its pitting resistance is slightly better than other steel grades. It has good machinability and weldability and can be used for pressure vessels.
Corrosion resistance of 1.4539 super austenitic stainless steel: Since the carbon content of 1.4539 is very low (maximum 0.020%), no carbide will precipitate under general heat treatment and welding. This eliminates the risk of intergranular corrosion after general heat treatment and welding. Due to the high chromium, nickel, and molybdenum content and the addition of copper, 1.4539 can be passivated even in reducing environments such as sulfuric acid and formic acid. The high nickel content also allows for a low corrosion rate in the active state.
In pure sulfuric acid in the concentration range of 0-98%, the use temperature of 1.4539 can be as high as 40 degrees Celsius. In pure phosphoric acid in the concentration range of 0-85%, its corrosion resistance is very good. In industrial phosphoric acid produced by wet process, impurities have a strong influence on corrosion resistance. In all kinds of phosphoric acid, 1.4539 has better corrosion resistance than ordinary stainless steel. In strongly oxidizing nitric acid, 1.4539 has lower corrosion resistance than high-alloyed steels without molybdenum. In hydrochloric acid, the use of 1.4539 is limited to lower concentrations of 1-2%. In this concentration range. 1.4539 has better corrosion resistance than conventional stainless steel. 1.4539 steel has high resistance to pitting corrosion.
Its resistance to crevice corrosion in chloride solutions is also very good. The high nickel content of 1.4539 reduces the corrosion rate in pits and crevices. Ordinary austenitic stainless steels may be sensitive to stress corrosion in a chloride-rich environment at temperatures above 60 degrees Celsius. This sensitization can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 1.4539 has a high resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide-rich environments.
1.4539 super austenitic stainless steel application areas:
1. Petroleum and petrochemical equipment, such as reactors in petrochemical equipment.
2. Storage and transportation equipment for sulfuric acid, such as heat exchangers.
3. Flue gas desulfurization equipment in power plants, the main use parts are: tower body, flue, baffle plate, internal parts, spray system, etc. of the absorption tower.
4. Scrubbers and fans in organic acid treatment systems.
5. Seawater treatment equipment, seawater heat exchangers, papermaking industry equipment, sulfuric acid and nitric acid equipment, acid making, pharmaceutical industry and other chemical equipment, pressure vessels, food equipment.
6. Centrifuges and reactors in pharmaceutical factories. 7.
Soy sauce tanks, cooking wine, salt tanks, equipment and dressing food machinery.
8. Equipment and components that are highly corrosive to dilute sulfuric acid.