1.4539 is super stainless steel

1.4539 super austenitic stainless steel is a low carbon, high nickel, molybdenum austenitic stainless acid-resistant steel. It has good activation-passivation transition ability, excellent corrosion resistance, good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, and good corrosion resistance in neutral chlorine-containing media. Excellent resistance to pitting corrosion, as well as good resistance to crevice corrosion and stress corrosion. It is suitable for sulfuric acid of various concentrations below 70°C. It can withstand acetic acid of any concentration and temperature under normal pressure and has good corrosion resistance in mixed acids of formic acid and acetic acid. Super austenitic stainless steel 904L is a high-alloy austenitic stainless steel with low carbon content. It has good corrosion resistance in dilute sulfuric acid and is specially designed for environments with harsh corrosion conditions. It has a high chromium content and sufficient nickel content. The addition of copper makes it highly acid-resistant, especially highly resistant to chloride gap corrosion and stress corrosion cracking. It is not prone to corrosion spots and cracks, and is resistant to spots. Its corrosion resistance is slightly better than other steel types, it has good processability and weldability, and can be used in pressure vessels.

1.4539 super stainless steel grades and standards:

904L, 00Cr20Ni25Mo4.5Cu (national standard), UNS N08904 (American Society of Motor Vehicles Engineers and American Society for Testing and Materials *** in 1967 Standards for the same design), DIN1.4539 (German standard), SUS890L, Al-904L, F904L, NAS 255

Executive standards: ASTM A240/ASME SA-240 (American Society for Testing and Materials standards; brand new The standard classifies it as a stainless steel series, and the original standard ASME SB-625 classifies it as a nickel-based alloy series), ASTM A276, ASTM A182/ASME SA-182, ASTM A312/ASMES A312

ASTM B625 /ASME B625, ASTM B673/ASME B673

1.4539 super stainless steel metallographic structure:?

1.4539 is a completely austenitic structure, which is different from the general austenitic stainless steel with high molybdenum content. In comparison, 904L is not sensitive to the precipitation of ferrite and α phase.

1.4539 Super Stainless Steel Processing Performance:

Welding Performance

Like general stainless steel, 904L can be welded using a variety of welding methods. The most commonly used welding methods are manual arc welding or inert gas shielded welding. The welding rod or wire metal is based on the composition of the base metal and has higher purity, and the molybdenum content is required to be higher than the base metal. Preheating is generally not required before welding, but in cold outdoor operations, in order to avoid condensation of water vapor, the joint part or adjacent area can be heated evenly. Pay attention to the local temperature not exceeding 100°C to avoid carbon accumulation and intergranular corrosion. When welding, small linear energy, continuous and fast welding speed should be used. Generally, heat treatment is not required after welding. If heat treatment is required, it must be heated to 1100~1150℃ and then cooled quickly.

Supporting welding materials and welding processes: ER385 welding wire and E385 electrode are used for welding 1.4539

Machining performance

The machining characteristics of 1.4539 are similar to other austenitic ones Made of stainless steel, there is a tendency for tool sticking and work hardening during processing. Carbide tools with positive rake angles must be used, and vulcanized and chlorinated oils should be used as cutting coolants. The equipment and processes should be based on reducing work hardening. During the cutting process, slow cutting speeds and feed rates should be avoided.

Corrosion resistance and main use environment of 1.4539:

1.4539 is an austenitic stainless steel with very low carbon content and high alloying designed for environments with harsh corrosion conditions. , has better corrosion resistance than 316L and 317L, takes into account both price and performance, and has high cost performance. Due to the addition of 1.5 copper, it has excellent corrosion resistance against reducing acids such as sulfuric acid and phosphoric acid.

It also has excellent corrosion resistance against stress corrosion, pitting corrosion and crevice corrosion caused by chloride ions, and has good resistance to intergranular corrosion. In pure sulfuric acid in the concentration range of 0-98, the service temperature of 904L can be as high as 40 degrees Celsius. In pure phosphoric acid with a concentration range of 0-85, its corrosion resistance is very good. In industrial phosphoric acid produced by wet processes, impurities have a strong impact on corrosion resistance. Among all kinds of phosphoric acid, 904L has better corrosion resistance than ordinary stainless steel. In strongly oxidizing nitric acid, 904L has lower corrosion resistance than highly alloyed steels that do not contain molybdenum. In hydrochloric acid, the use of 904L is limited to lower concentrations 1-2. within this concentration range. The corrosion resistance of 904L is better than that of conventional stainless steel. 904L steel has high resistance to pitting corrosion. Its resistance to crevice corrosion in chloride solutions. The force is also very good. The high nickel content of 904L reduces the corrosion rate in pits and crevices. Ordinary austenitic stainless steel may be sensitive to stress corrosion in a chloride-rich environment at temperatures above 60 degrees Celsius. This sensitivity can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 904L has high resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide-rich environments.

1.4539 application fields:

Petroleum and petrochemical equipment, such as reactors in petrochemical equipment, sulfuric acid storage and transportation equipment, such as heat exchangers, power plant flue gas desulfurization The main parts used in the device include: tower body, flue, door panel, internal parts, spray system, etc. of the absorption tower, scrubbers and fans in the organic acid treatment system, seawater treatment devices, seawater heat exchangers, and papermaking industry equipment. , sulfuric acid, nitric acid equipment, sulfuric acid, pharmaceutical industry and other chemical equipment, pressure vessels, food equipment, pharmaceutical factories: centrifuges, reactors, etc., plant foods: soy sauce tanks, cooking wine, salt tanks, equipment and dressings, for dilute sulfuric acid 904L is a matching steel grade for highly corrosive media.

Main specifications of 1.4539:

1.4539 seamless pipe, 1.4539 steel plate, 1.4539 round steel, 1.4539 forgings, 1.4539 flange, 1.4539 ring, 1.4539 welded pipe, 1.4539 steel strip, 1.4539 straight Strips, 1.4539 wire and supporting welding materials, 1.4539 round cake, 1.4539 flat steel, 1.4539 hexagonal rod, 1.4539 big and small heads, 1.4539 elbow, 1.4539 tee, 1.4539 processed parts, 1.4539 bolts and nuts, 1.4539 fasteners