ASME SB407 UNS N08810 Pipes for offshore oil and gas platforms
For offshore oil and gas platforms, ASME SB407 UNS N08810 (Incoloy 800H) pipes are highly regarded for their high strength, durability, and robust corrosion resistance in extreme high-temperature and high-pressure environments. However, selecting these pipes requires careful consideration of their specific properties and manufacturing requirements.
What is N08810?
UNS N08810 refers to Incoloy 800H, a high-temperature, corrosion-resistant nickel-iron-chromium alloy known for its excellent strength, oxidation resistance, and carburization resistance. Compared to base Incoloy 800, it features a higher carbon content and precisely controlled aluminum and titanium contents. This alloy is suitable for demanding applications such as petrochemical processing, power generation, and industrial furnaces, and excels in harsh, high-temperature environments.
Chemical Requirements for UNS N08810 Tube
|
Element |
Nickel |
Chromium |
Iron |
Manganese, max |
Carbon |
Copper |
Silicon |
Sulfur, max |
Aluminum |
Titanium |
|
Composition Limits, % |
30 min – 35 max |
19 min – 23 max |
36.5 min |
1.5 |
– |
0.75 |
1 |
0.015 |
0.15 min – 0.60max |
0.15 min – 0.60max |
Mechanical Properties of UNS N08811 Pipe and Tube
|
Alloy |
Condition (Temper) |
Tensile Strength |
Yield Strength (0.2 % offset, min) |
Elongation in 2 in. or 50 mm (0.8 in.), min |
|
UNS N08811 |
hot - finished annealed or cold - worked annealed |
65,000 (450) psi (MPa) |
25,000 (170) psi (MPa) |
30 |
Offshore Application Performance
High Temperature and High Pressure: Offshore platforms often use piping that handles high-temperature, high-pressure media, such as heat exchangers and process piping. The strength and stability of Incoloy 800H make it well-suited for these demanding conditions.
High Strength Requirements: Seamless Incoloy 800H piping offers improved mechanical properties, including higher tensile and yield strengths, making it ideal for handling the high internal pressures of offshore systems. Its seamless construction further enhances this pressure-bearing capability.
Reduced Thermal Stress: The alloy's extremely low thermal expansion reduces the risk of stress corrosion cracking, thereby improving safety and service life.
Resistant to Specific Process Gases: The material's resistance to carburizing and oxidizing atmospheres is critical for gas handling and transportation applications on offshore platforms.
Fabrication and Testing Requirements
Welding: Incoloy 800H can be welded using common welding processes such as TIG, plasma arc, and stick arc welding. Careful attention must be paid to controlling heat input and impurity contamination (sulfur, phosphorus, nitrogen, and oxygen) to prevent hot cracking. Suitable filler metals are required to maintain weld integrity.
Forming: The alloy exhibits good formability and can be formed using a variety of methods without compromising mechanical strength. However, due to its grain structure, extensive cold forming can result in an "orange peel" appearance.
Testing: Pipelines must be fully tested to meet ASME SB407 and specific offshore project requirements.
Mechanical Testing: Tensile strength, yield strength, elongation, and grain size must meet specifications. Grain size is measured using the planar method.
Nondestructive Testing (NDT): Offshore applications typically require 100% nondestructive testing (NDT), such as radiography or eddy current testing, to ensure the pipeline is free of discontinuities and defects. Hydrostatic testing: Pipes undergo hydrostatic testing to confirm their ability to withstand internal pressure.
Material Test Certificate (MTC): Documentation such as EN 10204/3.1B certificates are essential for confirming chemical composition and mechanical properties.
Gnee Steel specializes in the production of various nickel-based alloys. Gnee Steel's product packaging includes steel strapping: Pipes with an outer diameter of 3 inches or less are typically strapped together with polypropylene film to prevent rust during sea transportation, and then secured with steel strapping. Wooden boxes/crates: Pipes are typically packaged in wooden boxes or crates to protect them during transportation, especially those that are longer or have larger diameters. Seaworthy export packaging: Suppliers typically use standard seaworthy export packaging methods, which may include a variety of materials and techniques to protect the pipes during transportation. Tarpaulin packaging: This prevents rain, seawater, and other external factors from penetrating the export wooden crates during transportation. Gnee Steel specializes in the production and sale of alloy materials. Gnee Steel's products are widely used in aerospace, chemical, power, automotive, and nuclear energy industries, and we can provide customized alloy material solutions based on customer needs. For alloy material pricing inquiries or customized alloy material solutions, please contact us for a quote at ss@gneesteel.com.
