Slip-On (SO) flanges are a popular choice in oil and gas pipeline systems due to their flexibility during installation and strong, reliable joints. These flanges are designed to slide over the pipe and then be welded both internally and externally, creating a secure connection that can withstand high pressures and demanding operating conditions.
Manufactured according to international standards such as ASME, EN, DIN, and GB, these flanges ensure seamless integration with global pipeline systems and industrial projects.
SO flanges are widely utilized across different stages of oil and gas operations:
Upstream operations: connecting wellheads, separators, and initial flow pipelines.
Midstream transport: integrating pipelines, pumping stations, and compressor units.
Downstream processing: linking chemical processing equipment, refineries, and storage tanks.
Offshore platforms: suitable for harsh marine environments with high-pressure seawater exposure.
They are especially effective for medium to large diameter pipelines and systems that require periodic inspection or maintenance.
Simplified Installation – Slip-on design allows for quick alignment and welding, reducing assembly time.
Durable Leak-Resistant Joints – Double welding ensures strong, long-lasting connections.
High Pressure Capability – Compatible with pipelines ranging from PN2.5 to PN420 / ASME Class 150–2500.
Material Versatility – Available in carbon steel, stainless steel, and high-strength alloy steels.
Cost Efficiency – Requires less precision machining than weld neck flanges, lowering installation and maintenance costs.
Our SO flanges are available in a wide range of materials to meet diverse oil and gas applications:
Carbon Steel: ASTM A105, ASTM A350, Q235, Q345
Stainless Steel: ASTM F304, F304L, F316, F316L
Duplex & Super Duplex Steel: ASTM F51, F53, F55, S31803, S32205
Alloy Steel: ASTM F5, F9, F11, F22, F91
Nickel & Special Alloys: Inconel, Monel, Hastelloy
All products come with Mill Test Certificates (MTC) to ensure quality and traceability.
Our SO flanges meet international industry standards, including:
ASME / ANSI: B16.5, B16.47
European: EN 1092-1, DIN 86044
British: BS 4504, BS10
Chinese: GB/T 9115, HG/T 20592
This ensures that the flanges are fully compatible with global oilfield projects and EPC pipelines.
Verify pipe alignment before welding.
Follow proper welding procedures for each material and pressure rating.
Perform non-destructive testing (NDT) such as ultrasonic or radiographic inspections for high-pressure pipelines.
Schedule regular inspections to detect early signs of wear, corrosion, or leaks.
Wide size range: DN15 to DN3600 (1/2"–144")
Capable of handling high-pressure oil & gas pipelines
Manufactured with precision forging and CNC machining
Strict quality control and compliance with international standards
Engineered for long-term industrial reliability in demanding environments
Product Link: Slip-On Flange – Senrui Pipe
