1.4539 is a super stainless steel
1.4539 super austenitic stainless steel is a low-carbon, high-nickel, molybdenum austenitic stainless acid-resistant steel. Has a very good activation - passivation transformation ability, excellent corrosion resistance, in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, phosphoric acid has good corrosion resistance, in neutral chloride-containing media with good resistance to pitting corrosion, and at the same time has a good resistance to crevice corrosion and resistance to stress corrosion performance. Applicable to various concentrations of sulfuric acid below 70 ℃, in the normal pressure resistance of any concentration, any temperature of acetic acid and formic acid and acetic acid mixed acid corrosion resistance is also very good. Super austenitic stainless steel 904L is a kind of austenitic stainless steel with low carbon content and high alloy, which has good corrosion resistance in dilute sulfuric acid, and is specially designed for environments with harsh corrosive conditions. Has a high chromium content and sufficient nickel content, the addition of copper makes it has a strong acid resistance, especially for chloride interstitial corrosion and stress corrosion chipping has a high degree of resistance, not easy to etch spots and cracks, pitting corrosion resistance is slightly better than other steels, has a good machinability and weldability, can be used for pressure vessels.
1.4539 super stainless steel grades and standards:
904L, 00Cr20Ni25Mo4.5Cu (national standard), UNS N08904 (the American Society of Motor Vehicle Engineers and the American Society for Testing and Materials in 1967 *** with the design of the standard), DIN1.4539 (German standard), SUS890L, Al-904L, F904L, NAS 255
Executive standard: ASTM A240/ASME SA-240 (American Society for Testing and Materials standard; the new standard will be categorized as a series of stainless steel, the original standard ASME SB-625 will be categorized as a series of nickel-based alloys), ASTM A276, ASTM A182/ASME SA-182, ASTM A312/ASMES A312
ASTM B625/ASME B625, ASTM B673/ASME B673
1.4539 Super Stainless Steel Metallurgical Structure:?
1.4539 is a fully austenitic organization, compared with the general austenitic stainless steel with high molybdenum content, 904L is insensitive to precipitation of ferrite and alpha phase.
1.4539 Super Stainless Steel Processing Properties:
Welding Properties
As with general stainless steels, 904L can be welded using a wide variety of welding methods. The most commonly used welding methods for manual arc welding or sui gas shielded welding, welding rod or wire metal based on the composition of the base material and higher purity, molybdenum content requirements than the base material. Preheating is generally not required before welding, but in cold outdoor work, in order to avoid the condensation of water vapor, joints or adjacent areas can be uniformly heated. Note that the local temperature should not exceed 10 0 ℃, so as not to lead to carbon agglomeration, causing intergranular corrosion. Welding is recommended to use a small line energy, continuous and fast welding rate. After welding generally do not need heat treatment, such as the need for heat treatment, must be heated to 110 0 ~ 1150 ℃ after rapid cooling.
Supporting welding materials and welding process: 1.4539 welding selection of ER385 wire and E385 electrode
Machining performance
1.4539 machining characteristics similar to other austenitic stainless steel, machining process has a tendency to stick and hardening of the tool. Positive front angle carbide tools should be used, sulfurized and chlorinated oil as cutting coolant, equipment and process should be used to reduce the premise of work hardening. Slow cutting speeds and feeds should be avoided in the cutting process.
1.4539 corrosion resistance and the main use of the environment:
1.4539 is designed for corrosive conditions in harsh environments of a very low carbon content, high alloying austenitic stainless steel, better than the 316L and 317L corrosion resistance, while taking into account the price and performance, cost-effective. Due to the addition of 1.5% copper, it has excellent corrosion resistance to reducing acids such as sulfuric and phosphoric acids. It also has excellent corrosion resistance to stress corrosion, pitting and crevice corrosion caused by chloride ions, and good resistance to intergranular corrosion. In 0-98% concentration range of pure sulfuric acid, 904L can be used up to 40 degrees Celsius. In 0-85% concentration range of pure phosphoric acid, 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, 904L corrosion resistance is better than ordinary stainless steel. In strongly oxidizing nitric acid, 904L has lower corrosion resistance compared to highly alloyed steels without molybdenum. In hydrochloric acid, the use of 904L is limited to lower concentrations of 1-2%. In this concentration range, the corrosion resistance of 904L is better than that of conventional stainless steels. 904L steel has a high resistance to pitting corrosion. Its resistance to crevice corrosion in chloride solutions. The high nickel content of 904L reduces the rate of corrosion at pockmarks and crevices. Ordinary austenitic stainless steels can be sensitive to stress corrosion in a chloride-rich environment at temperatures above 60 degrees C. This sensitization can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 904L has a high resistance to stress corrosion rupture in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide rich environments.
1.4539 Application Areas:
Oil and petrochemical equipment, such as reactors in petrochemical equipment, etc., sulfuric acid storage and transportation equipment, such as heat exchangers, etc., flue gas desulfurization devices in power plants, the main use of the following parts: the tower of the absorption tower, flue gas ducts, stall door panels, the inner parts of the spray system, etc., the organic acid treatment system of the Scrubbers and fans, seawater treatment devices, seawater heat exchangers, paper industry equipment, sulfuric acid, nitric acid equipment, acid production, the pharmaceutical industry and other chemical equipment, pressure vessels, food equipment, pharmaceutical factories: centrifuges, reactors, etc., plant-based food: soy sauce tanks, cooking wine, salt tanks, equipment and dressings, for dilute sulfuric acid, strong corrosive media 904L is a matching steel.
1.4539 main specifications:
1.4539 seamless pipe, 1.4539 steel plate, 1.4539 round steel, 1.4539 forgings, 1.4539 flanges, 1.4539 rings, 1.4539 welded pipe, 1.4539 steel strips, 1.4539 straight bars, 1.4539 Wire and supporting welding material, 1.4539 round cake, 1.4539 flat steel, 1.4539 hexagonal bar, 1.4539 size head, 1.4539 elbow, 1.4539 tee, 1.4539 processing parts, 1.4539 bolts and nuts, 1.4539 fasteners