Weld Neck Flanges

Overview

Weld-neck flanges transfer bending and thermal stress smoothly from the flange into the pipe through a long tapered hub butt-welded to the line. This makes them the usual choice for higher-pressure, higher-temperature and cyclic duties where joint integrity is critical. FLOWTEC (UK) supplies weld-neck flanges configured to project scope, with the final specification confirmed at quotation stage.

At a glance

Welding-neck flanges for higher-pressure, higher-temperature and cyclic pipework, joined to the line by a butt weld. Configuration, materials and governing standard confirmed against your project specification.

• Long tapered hub carries bending and thermal load into the pipe
• Preferred where joint integrity is critical or the line cycles
• Referenced to ASME and EN design bases; raised-face standard, ring-type-joint available on higher-class configurations
• Materials and documentation confirmed at quotation stage

Typical applications

• High-pressure and high-temperature lines
• Cyclic and critical service
• Process and utility pipework

Typical use & selection context

Suited to process, utility and infrastructure pipework where the connection sees pressure cycling, elevated temperature or fatigue loading. Selection is driven by design pressure and temperature, pipe schedule/bore matching, facing and gasket strategy, and the governing standard — each confirmed against the line specification before recommendation.

Pressure class

ASME Class 150 - 2500 · EN 1092-1 PN 6 - 40 · ASME B16.47 Class 75 - 900

Size range

½″ - 24″ (DN 15 - 600) · 26″ - 60″ to ASME B16.47

Standards & facing context

Referenced against ASME B16.5 (typically ½″–24″) and ASME B16.47 for larger diameters, and EN 1092-1 Type 11 / DIN / GOST equivalents where the project calls for them. Indicative envelope: ASME Class 150–2500 or EN PN 6–40, sizes ½″–60″. Raised-face is standard; ring-type-joint facing is available on relevant higher-class weld-neck and blind configurations. Standards references are a design basis only, not a statement of certification.

Standards referenced

References below indicate the standards a configuration can be worked to. They are not a statement of certification — scope is confirmed per project.

• ASME B16.5 — Dimensional reference
• ASME B16.47 Series A & B — Large-diameter dimensional reference
• EN 1092-1 Type 11 — Dimensional reference
• BS 3293 — Project-specified reference

Materials & documentation

Carbon, low-alloy and stainless grades configured to order scope. Material and test documentation is confirmed against the purchase-order requirement; dimensional data is available on request for project review.

Documentation

Information to include in an enquiry

• Governing standard and class/PN
• Nominal size and schedule/bore
• Facing type
• Material grade
• Quantity
• Documentation required
• Application, fluid and operating conditions