Weld Neck Flange

Weld Neck Flange

Description

Weld Neck Flange is designed for high pressure and high temperature piping systems where structural integrity and fatigue resistance are critical. Weld Neck Flange features a long tapered hub which provides gradual stress transfer from the flange to the pipe, reducing stress concentration at the weld joint.

Weld Neck Flange is commonly used in critical services such as oil & gas pipelines, petrochemical plants, offshore platforms, LNG facilities and power plants. Because Weld Neck Flange is butt welded to the pipe, it provides excellent strength, sealing performance and long service life.

In many EPC piping projects, Weld Neck Flange is supplied together with stainless steel pipes and fittings as part of a complete piping material package.

Specifications / Standards

Manufactured according to international flange standards and piping specifications. Dimensions, pressure ratings, facing types and tolerances are controlled according to applicable standards.

Common standards include:

• ASME B16.5
• ASME B16.47 Series A / Series B
• EN 1092-1
• DIN Standards
• ISO 7005
• MSS SP-44

Inspection and certification can be supplied according to EN 10204 3.1 or EN 10204 3.2 with third-party inspection such as SGS, BV or TÜV if required by project specifications.

Often supplied together with butt weld pipe fittings and pipes for integrated piping system procurement.

Material Grades

Available in carbon steel, stainless steel, duplex stainless steel and nickel alloy materials suitable for various operating environments and corrosion conditions.

Common material grades include:

Carbon Steel
• ASTM A105
• ASTM A350 LF2

Stainless Steel
• ASTM A182 F304 / F304L
• ASTM A182 F316 / F316L
• ASTM A182 F321
• ASTM A182 F347

Duplex Stainless Steel
• ASTM A182 F51 (S31803)
• ASTM A182 F53 (S32750)
• ASTM A182 F55 (S32760)

Nickel Alloys
• ASTM B564 Alloy 625
• ASTM B564 Alloy 825
• ASTM B564 Alloy C276

Material selection depends on operating pressure, temperature, corrosion environment and project specifications.

Size Range

Size range typically includes:

• Size: 1/2” to 80”
• Pressure Rating: Class 150 / 300 / 600 / 900 / 1500 / 2500
• Facing Type: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)
• Suitable for various pipe wall thickness and schedules

Large diameter Weld Neck Flange can be manufactured according to project drawings and technical specifications for offshore, LNG and power plant projects.

Manufacturing Process

Typically manufactured from forged materials to ensure mechanical strength and pressure resistance.

Typical manufacturing process includes:

• Raw material inspection
• Cutting and forging
• Heat treatment
• Rough machining
• Finish machining
• Drilling
• Marking and traceability control
• Final inspection

For project supply, Weld Neck Flange may be supplied together with prefabrication pipe spools and piping components to reduce site welding work and improve installation efficiency.

Inspection & Testing

Inspection and testing are performed according to project specifications and applicable international standards.

Typical inspection includes:

• Visual inspection
• Dimensional inspection
• PMI (Positive Material Identification)
• Mechanical testing
• Hardness testing
• NDT testing if required
• Third-party inspection
• EN 10204 3.1 / 3.2 certification

Material traceability can be maintained from raw material heat number to final Weld Neck Flange marking and documentation package.

Applications / Industries

Widely used in industrial piping systems across many industries:

• Oil & Gas
• Petrochemical Plants
• LNG Projects
• Offshore Platforms / FPSO
• Power Plants
• Nuclear Projects
• Desalination Plants
• Chemical Plants
• Heavy Industrial Facilities

Weld Neck Flange is particularly suitable for high pressure, high temperature and critical service piping systems.

Packaging & Delivery

Weld Neck Flange is packed in wooden cases or wooden pallets suitable for international transportation. Anti-rust oil or protective coating is applied to prevent corrosion during shipment and storage.

Each flange marking typically includes:

• Size
• Pressure rating
• Material grade
• Heat number
• Standard
• Manufacturer identification

Shipping documents include packing list, commercial invoice, mill test certificates and inspection reports.

Why Choose Us

We supply Weld Neck Flange not only as individual flange products but also as part of engineered piping material packages for EPC contractors, project owners and industrial stockists.

Our supply scope includes pipes, fittings, flanges, plates, bars and prefabricated piping components manufactured according to international standards and project specifications.

With experience in supplying materials for oil & gas, petrochemical, offshore, LNG, power plant and heavy industrial projects, we understand project documentation requirements, inspection procedures and material traceability systems required by EPC contractors and end users.