2507 duplex stainless steel

2507 is a ferrite austenite (duplex) stainless steel (25cr-7ni-4mo-0.27n) 2507 stainless steel, which has excellent resistance to spot corrosion, crevice corrosion and uniform corrosion.
 
Main uses of 2507 stainless steel:
2507 is a kind of Ferritic Austenitic (duplex) stainless steel, which combines the most beneficial properties of many ferritic steels and austenitic steels. Because of the high content of chromium and molybdenum in the steel, it has excellent resistance to spot corrosion, crevice corrosion and uniform corrosion. The duplex microstructure ensures that the steel has high resistance to stress corrosion cracking and high mechanical strength.
 
2507 stainless steel is used in petroleum and natural gas industry; offshore oil platform (heat exchanger pipe, water treatment and water supply system, fire control system, water spray system, water stabilization system; petrochemical equipment; desalination (Desalination) equipment (and high-pressure pipe, sea water pipe in the equipment);
Mechanical and structural parts with high strength and corrosion resistance are required; gas (waste) purification equipment.
 
Main composition: 25cr-7ni-4mo-0.27n
 
National standard control:
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:
The high content of Cr and Mo in SAF2507 makes it have strong anti-corrosion ability to organic acids such as formic acid and acetic acid.
Compared with 904L, SAF2507 has stronger corrosion resistance to diluted sulfuric acid mixed with chloride ions. 904L is an austenitic alloy, which is specially used for pure sulfuric acid corrosion resistance.
316L grade can not be used in hydrochloric acid environment, it may suffer local corrosion or overall corrosion. SAF2507 can be used in diluted hydrochloric acid environment, with strong resistance to spot damage and crack corrosion.
 
2. Intergranular corrosion:
The lower carbon content of nsaf2507 greatly reduces the risk of carbide precipitation in intergranular during heat treatment. Therefore, this alloy has a strong resistance to intergranular corrosion related to carbides.
 
3. Stress corrosion cracking:
The compound structure of SAF 2507 makes it have strong ability to resist stress corrosion cracking. Because of its high alloy content, the corrosion resistance and strength of SAF2507 are better than 2205.
 
Cracks are almost inevitable in construction, which makes stainless steel more susceptible to corrosion in chloride environment. Saf 2507 has a strong ability to resist crack corrosion. Saf 2507 has an equal corrosion curve of 0.1 mm / year in sulfuric acid containing 2000 ppm chloride ion and 0.1 mm / year in hydrochloric acid.
 
Mechanical properties: saf 2507 has high compressive strength, impact strength, low coefficient of thermal expansion and high thermal conductivity. These properties are applicable to many structural parts and mechanical components. Saf 2507 has high impact strength and should not be placed in a temperature environment 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, e2594 welding rod
 
Applications: pulp and paper industry, desalination, flue gas purification, heat exchanger, chemical tanker piping system, seawater system, etc.
 
 
Main specification of 2507 stainless steel:
2507 stainless steel plate spot specification: 0.3mm-350mm (thickness)
2507 stainless steel bar stock specification: 3.0mm-500mm (diameter)
2507 stainless steel wire stock specification: 0.1mm-20mm (wire diameter)

 
Chemical composition of 2507 stainless steel

Chemical composition (%)
C	Si	Mn	Cr	Ni	s	P	Mo	N
≤0.03	≤0.80	≤1.2	24-26	6-8	≤0.02	≤0.035	3-5	0.24-0.32

After solution treatment, the microstructure of 2507 stainless steel has an ideal dual phase structure with a ratio of α / γ of about 50 / 50. When the solution temperature is above 1050 ℃, the amount of ferrite phase will increase with the increase of temperature. However, due to the high nitrogen content, the proportion of rigid phase below 1300 ℃ will not change significantly. If the steel is not aged (or heated) at different temperatures, there will be γ 2 formation and δ, χ, R, α ` intermetallic phase and Cr2N oxide precipitation on the α + γ matrix. As the carbon content in the steel is low (generally 0.01% - 0.02%), there is generally no carbide in the steel.
 
 
Mechanical properties of 2507 stainless steel pipe:
 
I. mechanical properties of 2507 duplex stainless steel pipe at room temperature:
Steel type: wall thickness ≤ 20mm;

Tensile strength	Yield strength	Elongation	Hardness
800-1000	≥550	≥ 25%	≥290

 
II. Mechanical properties of 2507 large caliber seamless pipe

OD × WT	Tensile strength	Yield strength	Elongation	Hardness
273.0mm × 4.19mm	≥894	≥644	≥40	≥284
323.9mm × 4.57mm	≥858	≥662	≥45	≥270
406.4mm × 4.74mm	≥854	≥ 657	≥41	≥272