Chemical Composition and Performance Characteristics of 2507 Stainless Steel Seamless Pipe
2507 stainless steel seamless pipe is a duplex stainless steel with a ferrite-austenite (duplex) microstructure and a chemical composition of 25Cr-7Ni-4Mo-0.27N. It has excellent resistance to pitting corrosion, crevice corrosion, and uniform corrosion. 2507 stainless steel seamless pipe combines the most beneficial properties of both ferritic and austenitic steels. Due to its high chromium and molybdenum content, it exhibits excellent resistance to pitting corrosion, crevice corrosion, and uniform corrosion. The duplex microstructure ensures high resistance to stress corrosion cracking, as well as high mechanical strength.
The main applications of 2507 stainless steel seamless pipe include the petroleum and natural gas industry, offshore oil platforms (heat exchanger tubes, water treatment and supply systems, fire protection systems, sprinkler systems, and ballast systems), petrochemical equipment, desalination (brackish water) equipment (including high-pressure pipes and seawater pipes), mechanical and structural components that require both high strength and high corrosion resistance, and gas purification equipment.
Chemical Composition of 2507 Stainless Steel Seamless Pipe: 25Cr-7Ni-4Mo-0.27N
Standards Comparison for 2507 Stainless Steel Seamless Pipe:
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 higher chromium and molybdenum content of SAF 2507 provide strong resistance to overall corrosion by organic acids such as formic acid and acetic acid. SAF 2507 alloy also exhibits strong corrosion resistance to inorganic acids, especially those containing chlorides.
Compared to 904L, SAF 2507 has stronger resistance to corrosion in diluted sulfuric acid containing chloride ions. 904L is an austenitic alloy specifically designed for resistance to pure sulfuric acid corrosion.
Grade 316L is not suitable for hydrochloric acid environments as it may experience localized or overall corrosion. SAF 2507 can be used in diluted hydrochloric acid environments and has strong resistance to pitting and crevice corrosion.
2. Intergranular corrosion:
The lower carbon content of SAF 2507 significantly reduces the risk of carbide precipitation in the intergranular regions during heat treatment, making the alloy highly resistant to intergranular corrosion associated with carbides.
3. Stress corrosion cracking:
The duplex structure of SAF 2507 provides strong resistance to stress corrosion cracking. Due to its higher alloy content, SAF 2507 exhibits superior corrosion resistance and strength compared to 2205.
Cracking is almost unavoidable in various applications, making stainless steel more susceptible to corrosion in chloride environments. SAF 2507 has excellent resistance to crack corrosion. In 2000 ppm chloride ion-containing sulfuric acid, the corrosion rate is 0.1 mm/year, and in hydrochloric acid, the corrosion rate is 0.1 mm/year.
Mechanical Properties: SAF 2507 has high compressive strength, impact strength, low thermal expansion coefficient, and high thermal conductivity. These properties make it suitable for many structural and mechanical components. SAF 2507 has high impact strength but should not be exposed to temperatures above 570°F for extended periods, as this may reduce its toughness. Tensile strength: σb ≥ 730 MPa; Elongation: δ ≥ 20%.
Matching Welding Consum
Matching Welding Consumables for 2507 Stainless Steel Seamless Pipe:
- Filler Wire: ER2594
- Welding Electrode: E2594
These welding consumables, specifically designed for duplex stainless steel, are recommended for welding 2507 stainless steel seamless pipes.
Applications of 2507 stainless steel seamless pipe include:
- Pulp and paper industry
- Seawater desalination
- Flue gas purification
- Heat exchangers
- Chemical tanker piping systems
- Seawater systems
Specifications for 2507 stainless steel seamless pipe:
- Thickness range for plate: 0.3mm-350mm
- Diameter range for rod: 3.0mm-500mm
- Diameter range for wire: 0.1mm-20mm
Chemical composition of 2507 stainless steel:
- Carbon (C): ≤0.03%
- Silicon (Si): ≤0.80%
- Manganese (Mn): ≤1.2%
- Chromium (Cr): 24-26%
- Nickel (Ni): 6-8%
- Sulfur (S): ≤0.02%
- Phosphorus (P): ≤0.035%
- Molybdenum (Mo): 3-5%
- Nitrogen (N): 0.24-0.32%
Microstructure of 2507 stainless steel seamless pipe:
After suitable solution treatment, the microstructure of this steel consists of an ideal alpha/gamma ratio of approximately 50/50 duplex structure. When the solution temperature is above 1050°C, the ferrite phase content in the steel increases with increasing temperature. However, due to the high nitrogen content, the proportion of the austenitic phase remains unchanged below 1300°C. Without different temperature aging or heating influences, gamma 2 formation, as well as precipitation of delta, chi, R, alpha' intermetallic phases, and Cr2N oxide, can occur on the alpha+gamma matrix. Due to the low carbon content in the steel (generally 0.01%-0.02%), carbides are generally not present.
Mechanical properties of 2507 stainless steel seamless pipe:
1. Room temperature mechanical properties:
- Wall thickness ≤ 20mm
- Tensile strength (δb): 800-1000 MPa
- Yield strength (δ0.2): ≥550 MPa
- Elongation (δ5): ≥25%
- Hardness (HV): 290
2. Mechanical properties from room temperature to -200°C:
- Tensile strength (δb) at room temperature: ≥530 MPa
- Tensile strength (δb) at 100°C: ≥450 MPa
- Tensile strength (δb) at 200°C: ≥400 MPa
3. Mechanical properties of large-diameter seamless pipes:
- Outer diameter × wall thickness: 273.0mm × 4.19mm
- Tensile strength (δb): 894 MPa
- Yield strength (δ0.2): 644 MPa
- Elongation (δ5): 40%
- Hardness (HV): 284
- Outer diameter × wall thickness: 323.9mm × 4.57mm
- Tensile strength (δb): 858 MPa
- Yield strength (δ0.2): 662 MPa
- Elongation (δ5): 45%
- Hardness (HV): 270
- Outer diameter × wall thickness: 406.4mm × 4.74mm
- Tensile strength (δb): 854 MPa
- Yield strength (δ0.2): 657 MPa
- Elongation (δ5): 41%
- Hardness (HV): 272
also can do grade S31803 S32205 S32750 bar plate pipe fittings flange sheet coil etc
