Chemical composition and properties of 2507 stainless steel seamless pipe
Chemical composition and performance characteristics of 2507 stainless steel seamless pipe
UNS S32750 (2507) stainless steel seamless pipe is a Ferritic Austenitic (duplex) stainless steel with chemical composition (25cr-7ni-4mo-0.27n) 2507 stainless steel, which has excellent resistance to pitting corrosion, crevice corrosion and uniform corrosion. 2507 stainless steel seamless pipe is a kind of Ferritic Austenitic (duplex) stainless steel. It combines the most beneficial properties of many Ferritic and austenitic steels. Due to the high content of chromium and molybdenum, the steel has excellent resistance to spot corrosion, crevice corrosion and uniform corrosion. The dual phase microstructure ensures that the steel has high resistance to stress corrosion cracking and high mechanical strength.
Main uses of super duplex steel 2507 stainless steel seamless pipe: 2507 stainless steel is used in oil and natural gas industry; Offshore skyshatter oil platform (heat exchanger pipe, water treatment and water supply system, fire protection system, sprinkler system, water stabilization system; petrochemical equipment; desalination (Desalination) equipment (and high-pressure pipe and seawater pipe in the equipment); Mechanical and structural components with high strength and high corrosion resistance are required; Fuel (waste) gas purification equipment.
2507 duplex stainless steel seamless pipe main composition: 25cr-7ni-4mo-0.27n
Comparison of national grade standards of super duplex steel 2507 stainless steel:
ASTM/ASME: A240 - UNS S32750
EURONORM: 1.4410 - X2 Cr Ni MoN 25.7.4
AFNOR: Z3 CN 25.06 Az
DIN/EN： 1.4410、ASME SA-240
GB: 25Cr-7Ni-4Mo-0.27N
Corrosion resistance
1. General corrosion:
Saf 2507 has strong overall corrosion resistance to organic acids such as formic acid and acetic acid due to its high content of chromium and molybdenum. SAF2507 alloy also has strong corrosion resistance to inorganic acids, especially those containing chlorides.
Compared with 904L stainless steel plate, super duplex steel SAF2507 has stronger corrosion resistance to diluted sulfuric acid mixed with chloride ions. Stainless steel pipe 904L is an alloy in austenitic state, which is specially used to resist pure sulfuric acid corrosion.
316L stainless steel seamless pipe grade cannot be used in hydrochloric acid environment. It may be subject to local corrosion or overall corrosion. SAF2507 can be used in diluted hydrochloric acid environment and has strong resistance to spot damage and crack corrosion.
2. Intergranular corrosion:
The lower carbon content of NSAF 2507 greatly reduces the risk of carbide precipitation in intergranular during heat treatment. Therefore, this alloy has strong resistance to carbide related intergranular corrosion
3. Stress corrosion cracking:
The compound structure of SAF 2507 makes it have strong resistance to stress corrosion cracking. Due to its high alloy content, the corrosion resistance and strength of SAF 2507 are better than 2205
Cracks are almost inevitable in construction and other aspects, which makes stainless steel more vulnerable to corrosion in chloride environment Saf 2507 has strong crack corrosion resistance Equal corrosion curve of SAF 2507 in sulfuric acid containing 2000ppm chloride ion is 0.1 mm / year; Isocorrosion curve in hydrochloric acid 0.1 mm / year
Mechanical properties: saf 2507 has high compressive strength, impact strength, low coefficient of thermal expansion and high thermal conductivity These characteristics are applicable to many structural parts and mechanical components Saf 2507 has high impact strength and should not be placed at a temperature higher than 570 ° f for a long time, which may weaken its toughness Tensile strength: σ b≥730Mpa; Elongation: δ ≥20%
Supporting welding materials: er2594 welding wire and e2594 welding rod
2507 dual phase steel pipe, S32750 dual phase steel pipe fittings, S31803 dual phase steel flange application fields: pulp and paper industry, seawater desalination, flue gas purification, heat exchanger, chemical tanker pipeline system, seawater system, etc.
Main specifications of 2507 stainless steel:
2507 stainless steel seamless pipe spot specification: 19mm-350mm (diameter)
2507 stainless steel plate stock specification: 0.3mm-350mm (thickness)
2507 stainless steel bar stock specification: 65.0mm-300mm (diameter)
Chemical composition of 2507 stainless steel:
C≤0.03 、Si≤0.80 、Mn≤1.2 、Cr:24-26 、Ni:6-8 、S≤0.02 、P≤0.035 、Mo:3-5 、N:0.24-0.32
2507 stainless steel seamless pipe has ideal microstructure after suitable solution treatment α/γ A biphasic structure with a ratio of about 50 / 50. When the solid solution temperature is above 1050 ℃, the number of ferrite phase in steel will increase with the increase of temperature, but due to the high nitrogen content, the proportion of rigid phase below 1300 ℃ will not change significantly. If the steel is not aged at different temperatures (or affected by heat), it will α+γ There will be on the substrate γ 2 formation and δ、χ、 R、 α` Intermetallic phase and Cr2N and other oxides precipitate. Because the carbon content in steel is low (generally 0.01% - 0.02%), there is generally no carbide in steel.
Mechanical properties of 2507 stainless steel seamless pipe products:
1、 Mechanical properties of 2507 stainless steel seamless pipe at room temperature:
2、 Mechanical properties of 2507 duplex stainless steel plate at room temperature:
3、 Mechanical properties of 2507 large diameter seamless pipe:
δ b/MPa:800-1000 、 δ 0.2/MPa:≥550 、 δ 5 /%: ≥ 25, hardness (HV): 290
