Overview of 904L super stainless steel;
904L super austenitic stainless steel belongs to low carbon, high nickel and high molybdenum austenitic stainless and acid-resistant steel, which is a proprietary material imported from H S company in France. It has good activation-passivation conversion ability, excellent corrosion resistance, good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid and phosphoric acid, good pitting corrosion resistance in neutral chlorine-containing media, and good crevice corrosion resistance and stress corrosion resistance. It is suitable for sulfuric acid with various concentrations below 70℃, and has good corrosion resistance in acetic acid with any concentration and temperature and mixed acid of formic acid and acetic acid under normal pressure. Super austenitic stainless steel 904L is a kind of high-alloy austenitic stainless steel with low carbon content, which has good corrosion resistance in dilute sulfuric acid and is specially designed for harsh corrosion conditions. It has high chromium content and sufficient nickel content. The addition of copper has strong acid resistance, especially high resistance to chloride crevice corrosion and stress corrosion cracking, and corrosion spots and cracks are not easy to appear. The pitting corrosion resistance is slightly better than other steels, and it has good machinability and weldability, and can be used for pressure vessels.
Brand and standard of 904L super stainless steel:
00Cr20Ni25Mo4.5Cu (national standard), UNS N08904 (standard designed by American Society of Automotive Engineers and American Society of Materials and Testing in 1967 * *), DIN 1.4539 (German standard), ASTM A240 (American Society of Materials and Testing standard; The new standard classifies it as stainless steel series, and the original standard ASME SB-625 classifies it as nickel-based alloy series and SUS890L.
Metallographic structure of 904L super stainless steel:?
904L has a completely austenitic structure. Compared with ordinary high molybdenum austenitic stainless steel, 904L is insensitive to the precipitation of ferrite and α phase.
Cutting performance of 904L super stainless steel;
welding performance
Like ordinary stainless steel, 904L can be welded by various welding methods. The most commonly used welding method is manual arc welding or inert gas shielded welding. Covered electrode or welding wire metal is based on the composition of base metal, which has high purity and requires molybdenum content higher than that of base metal. Generally, preheating is not required before welding, but when working outdoors in cold weather, to avoid condensation of water vapor, the joint parts or adjacent areas can be heated uniformly. Note that the local temperature should not exceed 10 0℃ to avoid carbon deposition and intergranular corrosion. Small line energy, continuous and fast welding speed should be adopted in welding. Generally, heat treatment is not required after welding. If heat treatment is needed, it must be heated to1100 ~1150℃ and then quickly cooled.
Matching welding materials and welding technology: ER385 welding wire and E385 covered electrode are selected for 904L welding.
machinability
The processing characteristics of 904L are similar to those of other austenitic stainless steels, and there is a tendency to stick to the knife and harden during processing. Carbide cutter with positive rake angle should be used, and vulcanized and chlorinated oil should be used as cutting coolant. Equipment and technology should be based on reducing work hardening. Slow cutting speed and feed speed should be avoided during cutting.
Corrosion resistance and main use environment
904L is a low-carbon and high-alloy austenitic stainless steel, which is designed for harsh corrosive environment. Compared with 3 16L and 3 17L, 904L has better corrosion resistance, which gives consideration to both price and performance, and has higher cost performance. Due to the addition of 1.5% copper, it has excellent corrosion resistance to reducing acids such as sulfuric acid and phosphoric acid. It also has excellent corrosion resistance to stress corrosion, pitting corrosion and crevice corrosion caused by chloride ion and good intergranular corrosion resistance. In the concentration range of 0-98%, the service temperature of 904L can be as high as 40 degrees Celsius. The corrosion resistance of pure phosphoric acid is very good in the concentration range of 0-85%. In industrial phosphoric acid produced by wet process, impurities have great influence on corrosion resistance. Among all kinds of phosphoric acid, the corrosion resistance of 904L is better than that of ordinary stainless steel. In strongly oxidizing nitric acid, the corrosion resistance of 904L is lower than that of high alloy steel without molybdenum. In hydrochloric acid, the use of 904L is limited to the lower concentration of 1-2%. In this concentration range. The corrosion resistance of 904L is better than that of conventional stainless steel. 904L steel has high pitting resistance. Its crevice corrosion resistance in chloride solution. The strength is also very good. The high nickel content of 904L reduces the corrosion rate in pits and cracks. When the temperature is higher than 60 degrees Celsius, ordinary austenitic stainless steel may be sensitive to stress corrosion in chloride-rich environment. This sensitivity can be reduced by increasing the nickel content in stainless steel. Due to the high nickel content, 904L has high stress corrosion cracking resistance in chloride solution, concentrated hydroxide solution and environment rich in hydrogen sulfide.
904L application field
Petrochemical equipment, such as reactors in petrochemical equipment, sulfuric acid storage and transportation equipment, such as heat exchangers, flue gas desulfurization devices in power plants, are mainly used in towers, flues, baffles, absorber internals and spray systems in organic acid treatment systems, scrubbers and fans, seawater treatment devices, seawater heat exchangers, paper industry equipment, sulfuric acid and nitric acid equipment, acid production, pharmaceutical industry and other chemical equipment. Pharmaceutical factory: centrifuges, reactors, etc. Plant food: soy sauce cans, cooking wine, salt cans, equipment and dressings, which are suitable for 904L, a medium with strong corrosiveness to dilute sulfuric acid.
Main specifications of 904L:
904L seamless pipe, 904L steel plate, 904L round steel, 904L forging, 904L flange, 904L ring, 904L welded pipe, 904L steel belt, 904L straight bar, 904L welding wire and its supporting welding materials, 904L round cake, 904L flat steel, 904L hexagon bar, 904L big head, 904L steel belt.
3 10S/ 2520/ 1.4845 stainless steel
Introduction of 3 10S: 3 10S stainless steel has good high temperature resistance. When the temperature exceeds 800℃, it begins to soften and the allowable stress begins to decrease. The maximum service temperature is 1200℃. Because of the high content of nickel (Ni) and chromium (Cr), it has good oxidation resistance, corrosion resistance, acid and alkali resistance and high temperature resistance. The high-temperature resistant steel pipe is specially used for manufacturing electric furnace pipes and other occasions. With the increase of carbon content in austenitic stainless steel, its strength is improved due to its solid solution strengthening effect. The chemical composition of austenitic stainless steel is based on chromium and nickel, and elements such as molybdenum, tungsten, niobium and titanium are added. Because of its face-centered cubic structure,
The application fields of 3 10 are: petroleum, electronics, chemical industry, medicine, textile, food, machinery, construction, nuclear power, aerospace, military industry and other industries.
? 3 10S Main specifications:
3 10S seamless pipe? 3 10S steel plate, 3 10S round steel, 3 10S forgings, 3 10S flange,? 3 10S ring? 3 10S welded pipe, 3 10S steel strip, 3 10S straight bar,? 3 10S welding wire materials and supporting welding materials. 3 10S round cake? 3 10S flat steel, 3 10S hexagonal bar,? 3 10S size head,? 3 10S elbow,? 3 10S tee,? 3 10S machined parts. 3 10S bolt and nut. 3 10S fastener
2205/UNS S32205 Dual Phase Steel
2205 international common name:
2205 dual-phase steel, UNS S32205, UNS S32205, NAS 329J3L, F5 1, W.-Nr. 1.4462，00Cr22Ni5Mo3N。
2205 implementation standard:
Green TM A240/ASME SA-240, ASTM A276, ASTM A/KOOC-0/82/ASME SA-/KOOC-0/82, ASTM A3/KOOC-0/2/ASME A3/KOOC-0/2.
2205 physical properties:
Density of 2205 dual-phase steel: 7.98g/cm3, melting point: 1300- 1390℃.
2205 heat treatment:
Keep the temperature between 1000- 1050℃ 1-2 hours, and air-cool or water-cool quickly.
2205 mechanical properties:
Tensile strength: σb≥795Mpa, yield strength σb≥550Mpa, elongation: δ≥ 15%, hardness ≤3 10(HB).
2205 Corrosion resistance and main use environment:
Compared with 3 16L and 3 17L austenitic stainless steels, 2205 duplex stainless steel 2205 alloy is superior in pitting corrosion resistance and crack corrosion resistance, with higher corrosion resistance, lower thermal expansion coefficient and higher thermal conductivity than austenite. Compared with austenitic stainless steel, the compressive strength of duplex stainless steel 2205 alloy is twice that of austenitic stainless steel. Compared with 3 16L and 3 17L, designers can reduce their weight. Alloy 2205 is especially suitable for the temperature range of-50 F/+600 F, and can also be used at lower temperatures under strict restrictions (especially for welded structures).
2205 welding materials and welding technology;
ER2209 welding wire and E2209 covered electrode are selected for the welding of 2205 dual-phase steel.
2205 application fields are:
Oil and gas industry equipment;
Offshore platforms, heat exchangers, underwater equipment and fire fighting equipment;
Chemical processing industry, container and pipeline industry;
Seawater desalination, high-pressure reverse osmosis equipment and submarine pipelines;
Energy industry, such as FGD system, industrial washing system and absorption tower used for desulfurization and denitrification in power plants;
Mechanical parts (high strength, corrosion-resistant and wear-resistant parts).
2205 main specifications:
2205 seamless pipe, 2205 steel plate, 2205 round steel, 2205 forging, 2205 flange, 2205 circular ring, 2205 welded pipe, 2205 steel strip, 2205 straight bar, 2205 welding wire and its supporting welding materials, 2205 round cake, 2205 flat steel, 2205 hexagonal bar, 2205 large and small head, 2205
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