Products Description
Product Specifications
| Standards | ASTM A928 / ASME SA928 |
| Steel Grades | UNS S31200 S31260 S31500 S31803 S32003 S32101 S32202 S32205 S32304 S32506 S32550 S32900 S32950 S32760 S32520 S81921 882121 S82441 |
| Equivalent Standards | EN 1.4410 / F53 / SAF 2507 |
| Outer Diameter (OD) | 3 mm – 609.6 mm |
| Wall Thickness (WT) | 0.5 mm – 32 mm |
| Length |
6m / 12m,up to 18m (customizable) |
| Surface Treatment | Pickled & Passivated |
| Production Process | ERW,EFW |
| Condition | Solution Annealed |
Grade 2507 exhibits excellent weldability and can be joined using the following methods: SMAW, GTAW, PAW, FCW, and SAW. When welding 2507, it is recommended to utilize 2507/P100 filler metals (welding wire ER2594; welding electrode E2594); this ensures the formation of an appropriate duplex microstructure, thereby meeting the specific requirements for field welding in geothermal projects.
ASTM A928 UNS S32750 Super Duplex tubing is suitable for service within the temperature range of 150–280°C. With a Pitting Resistance Equivalent Number (PREN) of ≥40, it effectively resists pitting corrosion, crevice corrosion, and chloride stress corrosion cracking in geothermal waters characterized by high chloride ion concentrations and high salinity.
The corrosion resistance of UNS S32750 is 3 to 4 times greater than that of 316L, while its mechanical strength exceeds that of 316L by more than twofold. In contrast, 316L is susceptible to stress corrosion cracking and pitting corrosion in geothermal environments, making it unsuitable for long-term buried service applications.
Customized Services
- TORICH offers customized sizing services tailored to the specific requirements of various geothermal pre-installation projects. Available dimensions include an outer diameter ranging from 3 mm to 609.6 mm (extending up to a maximum of 1200 mm), a wall thickness between 0.5 mm and 32 mm, and a maximum length of 18 meters.
- In addition to a standard pickled finish, the ASTM A928 UNS S32750 Super Duplex Tube is available with various surface treatments, including mechanical polishing and specialized anti-corrosion coatings such as epoxy resin and polyethylene.
Chemical Composition
| Element | Chromium | Nickel | Molybdenum | Nitrogen | Manganese | Silicon | Carbon | Phosphorus | Sulfur | Iron |
| Composition (%) | 24.0 – 26.0 | 6.0 – 8.0 | 3.0 – 5.0 | 0.24 – 0.32 | ≤ 1.2 | ≤ 0.8 | ≤ 0.030 | ≤ 0.035 | ≤ 0.020 | Balance |
Mechanical Properties
| Property | Tensile Strength | Yield Strength | Elongation | Hardness | Impact Toughness | Density | Modulus of Elasticity |
| Value | ≥ 795 MPa | ≥ 550 MPa | ≥ 15% | ≤ 310 HBW | Excellent | 7.8 g/cm³ | ~200 GPa |
Possible Alternative Grades
- Alloy 625 (Nickel Alloy): A premium nickel-based alloy offering excellent resistance to heat and chemical corrosion. It is significantly more expensive but ideal for extreme environments in chemical and aerospace applications.
- 316L Stainless Steel (Austenitic Stainless Steel): A commonly used stainless steel with good corrosion resistance in moderate environments. It lacks the strength and localized corrosion resistance of S32750, making it suitable only for lower-risk applications.
- Titanium Grades 2 and 5: Titanium provides outstanding corrosion resistance and a high strength-to-weight ratio. Grade 2 is known for seawater resistance and bio-compatibility, while Grade 5 offers greater mechanical strength. These are excellent choices where weight reduction and maximum corrosion resistance are critical.
Applications areas
2507 Super Duplex tubing is designed for use in harsh geothermal environments characterized by high chloride concentrations, high salinity, and moderate-to-high temperatures. It is utilized in a wide range of geothermal piping applications, including fluid transport and subsurface installation, such as:
Geothermal brine transmission lines, reinjection pipelines within geothermal systems, geothermal heating system piping, heat exchanger and plant process piping, direct-buried underground lines, trench-laid pipelines, and main trunk lines for ground-source heat pumps. The tubing boasts a service life of at least 30 years and a maximum long-term operating temperature of 280°C, thereby fully meeting the requirements of the vast majority of moderate-to-high-temperature geothermal projects.
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Products Package
We offer a wide range of packaging options, including plastic end caps, woven bags, wooden crates, and iron frames. Custom packaging solutions, logo branding, and other personalized requirements are also available to meet specific customer needs.
FAQ
Q: Can this pipe be used in geothermal water with high chloride ion content?
A: Yes. Its pitting resistance equivalent (PREN) ≥40 can withstand pitting and stress corrosion cracking in geothermal water with chloride ion content up to 50,000 ppm, making it suitable for most high-mineralization geothermal environments.
Q: How to prevent corrosion of the pipe buried in soil?
A: The standard surface treatment is acid pickling and passivation (AP), which improves corrosion resistance. For extremely harsh soil corrosion environments, special anti-corrosion coatings such as epoxy resin and polyethylene are available. It is also recommended to use insulating gaskets to isolate the pipe from the carbon steel pipe to avoid galvanic corrosion.
Q: Does S32750 meet the service standards for acidic conditions in the oil and gas industry?
A: Yes. It meets the requirements of NACE MR0175 / ISO 15156 and is suitable for use in geothermal systems containing H₂S and CO₂.
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