Large Diameter Hot-Expanded Seamless Steel Pipes - The Preferred Material For Long-Distance Pipeline Infrastructure

Large-diameter hot-expanded Seamless Steel Pipes are core components of modern industrial pipeline systems and are widely used in energy, the chemical industry, infrastructure, and other fields because of their excellent pressure-bearing capacity, corrosion resistance, and adaptability to complex working conditions.

PETROL STEEL CO., LTD. is a professional supplier of large-diameter hot-expanded Seamless Steel Pipes. Our company uses the hot expansion process to increase the diameter of small-diameter Seamless Steel Pipes to Φ508 mm-Φ1420 mm, giving large-diameter hot-expanded Seamless Steel Pipes the strength of seamless pipes and the large-diameter benefits of welded pipes.

The core performance indicators of large diameter hot-expanded Seamless Steel Pipes include: Mechanical properties: tensile strength ≥485MPa, yield strength ≥245MPa (taking Q345 as an example); corrosion resistance: can be improved by internal and external coatings (3PE, FBE) or galvanizing, dimensional accuracy: outer diameter tolerance ±1%, wall thickness tolerance ±10%.

The connection and installation methods of large-diameter hot-expanded seamless steel pipes include the following: connection method: welding (double-sided submerged arc welding), flange connection or mechanical coupling; installation angle: support horizontal, vertical and inclined installation (need to cooperate with the support and hanger system); and pressure level: PN10-PN160 (up to 16 MPa).

The process and quality control of large-diameter hot-expanded seamless steel pipes include thermal expansion process verification and temperature control, with an expansion temperature ≤ 900℃ to avoid grain coarsening and a forced water cooling method to increase yield strength by 15%.

The list of mandatory inspection items for large diameter hot-expanded seamless steel pipes before leaving the factory includes the following: Non-destructive testing: 100% ultrasonic flaw detection (GB/T 5777) [68]; mechanical properties: transverse tensile test (yield strength ≥355 MPa) [10]; corrosion test: H₂S environment requires NACE TM0177 standard sulphur resistance test.

The use environment of large diameter hot-expanded seamless steel pipes includes: Applicable media: crude oil, natural gas, steam, acid and alkali solution (material matching required); working temperature: -40℃~450℃ (impact test required for low temperature); environmental requirements: extreme environments such as land, sea and polar regions (special anti-corrosion design required).

Large-diameter hot-expanded seamless steel pipes have many advantages, including but not limited to the following: Economical: 20%-30% lower cost than traditional cast pipes; long service life: design life ≥30 years (in line with API 5L/GB/T 5310 standards); fast delivery: hot expansion process shortens the production cycle by more than 50%.

The application scenarios and cases for large-diameter hot-expanded seamless steel pipes include the following:
Applications in energy transmission systems include the petroleum and natural gas industries: China-Russia East Line Natural Gas Project (Φ1420mm X80 steel grade); power industry: supercritical boiler high-temperature steam pipeline (P91 material); municipal industry: urban heating pipeline network (prefabricated insulation pipe structure);
As steam pipelines, in the main application of supercritical generator sets, ASTM A335 P91 material hot-expanded pipes (such as specifications 530×20 mm) are used, with a temperature resistance of 650℃ applied to the boiler superheater system 35; process requirements: forced normalising + tempering treatment, grain size ≥8 grade.
Applications in infrastructure and chemical engineering include the following: as a large bridge pier, 480×20 mm 16Mn steel with compressive strength ≥490 MPa, extending the life of the bridge by 30%; as a chemical reactor support, a 426×30 mm Alloy Steel Pipe, resistant to hydrogen sulphide corrosion (sulphur content ≤0.005%); as a city heating network pipeline, 630×10 mm P265GH, EN 10216-2 standard, -50℃ low temperature toughness meets the standard; a refining base uses a 426×30 mm thermal expansion pipe to support the reactor, reducing the vibration stress of the equipment by 40%.
Applications in ship and marine engineering projects include the following: as a ship hydraulic pipeline system, a 480×20 mm 16Mn seamless pipe is used for steering gear hydraulic pipelines, with a pressure of 35 MPa, and the internal defects are detected by magnetic flaw detection.

As a structural pipe, in the application of offshore platform projects, a 720×14 mm thermal expansion pipe is used as a conductor frame support with a 3PE anti-corrosion coating, and the anti-seawater corrosion life exceeds 25 years. The LNG fuel-powered ship pipeline, a double-wall hot expansion pipe (material 022Cr17Ni12Mo2), transports low-temperature liquefied gas with no brittle cracking at -196℃.
Application in special industrial scenarios, such as a nuclear power primary loop pipeline pipe, ASME SA335 standard 820×14 mm hot expansion pipe, 100% ultrasonic flaw detection to ensure zero defects; high-pressure boiler parts T/CISA 002-2017 standard 630×9 mm products, used for the power station boiler economiser.

PETROL STEEL CO., LTD produces the following materials of the large-diameter hot-expanded seamless steel pipes:

International: API 5L, ASTM A106/A335
Domestic: GB/T 5310, SY/T 5037
Industry certification: ISO 9001, CE/PED
ASTM A106 Gr. A,
ASTM A106 Gr. B,
ASTM A106 Gr. C,
ASTM A333 Gr.3,
ASTM A333 Gr.6,
ASTM A335 P5,
ASTM A335 P91,
EN 10216-1/2 P235GH,
EN 10216-1/2 P265GH.

Contact us today at sales@petrolsteel.com or WhatsApp: +86 159 0035 7871 for the best price and instant delivery.

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