Welded connections
Weld Neck Flanges
A tapered hub carries the connection from the flange body to a butt-welded pipe end. The pipe bore and wall thickness are important parts of the flange specification.
Product catalogue
Flanges
Explore connection types, compare their construction and specify the details for your project.
23 flange types
Drawing-based enquiry
Welded connections
Slip-On Flanges
The flange bore slips over the pipe before the connection is secured with fillet welds. Pipe outside diameter and installation clearance govern the fit.
Closure & measurement
Blind Flanges
A solid flange closes a flanged opening without a through bore. Its bolted connection allows the closure to be removed for access when the system is safely isolated.
Mechanical connections
Threaded Flanges
Internal threads connect the flange to a matching threaded pipe end. The thread form, nominal size and mating pipe specification must be stated together.
Welded connections
Socket Weld Flanges
A recessed socket receives the pipe end, with a fillet weld at the outside of the hub. Socket depth, bore and assembly requirements distinguish it from a slip-on connection.
Mechanical connections
Lap Joint Flanges
A backing flange works with a separate stub end or lapped pipe end. The stub end provides the gasket seating surface while the backing flange transmits the bolt load.
Welded connections
Long Weld Neck Flanges
An extended neck combines a flanged connection with a longer nozzle section. Neck length, bore and end preparation must be specified for the intended equipment connection.
Closure & measurement
Orifice Flanges
Pressure-tapping connections distinguish an orifice flange from a general pipe flange. A matched assembly supports the differential-pressure measurement arrangement around an orifice plate.
Mechanical connections
Companion Flanges
A companion flange is selected to mate with a particular flanged connection. The term describes its role in an assembly, so the actual connection form and dimensions must be identified.
Construction & special designs
Plate Flanges
A plate flange is a ring-shaped component made from plate, with an open bore and a bolt pattern specified for the mating connection. Plate construction is distinct from a flat gasket facing.
Welded connections
Reducing Flanges
A reducing flange combines a larger mating-flange interface with a smaller pipe connection or bore. Both the mating size and the reduced connection must be identified.
Branch connections
Weldo Flanges
A Weldo flange combines a flanged branch connection with a weld-on outlet form at the run pipe. The branch-to-run interface is a defining part of the requirement.
Branch connections
Nipo Flanges
A Nipo flange is a flanged branch-outlet form with a nipple-like extended neck. Projection and the run-pipe attachment must be defined as part of the complete branch.
Construction & special designs
Forged Flanges
Forged flanges describe a manufacturing route spanning several connection forms, including weld neck, slip-on and blind. The flange type must still be specified.
Mechanical connections
Loose Flanges
A loose flange is a separate backing component working with a collar, lapped end or stub end. It transfers bolt load while the companion component forms the pipe-side seating interface.
Construction & special designs
Square Flanges
A square flange has a square external form and a connection-specific bolt arrangement. The outer shape alone does not identify its bore, seal or pressure rating.
Welded connections
Expander Flanges
An expander flange incorporates a transition between a smaller pipe-side connection and a larger flanged bore. The transition geometry is part of the component design.
Closure & measurement
High Hub Blind Flanges
A high hub blind flange combines a closed centre with a projecting hub on its rear side. The hub profile distinguishes it from an ordinary flat-backed blind flange.
Closure & measurement
Spectacle Blinds
A spectacle blind joins a solid blank and an open ring with a connecting bridge. One side or the other is positioned in the flange joint to define the line condition.
Closure & measurement
Spades / Paddle Blinds
A spade is a solid line blank with a handle, installed between flanges for a specified isolation condition. It is used with a separately identified matching spacer arrangement.
Closure & measurement
Ring Spacers
A ring spacer is the open component of a separate spade-and-spacer arrangement. Its bore permits the intended flow path while maintaining the specified flange-joint spacing.
Construction & special designs
Lip-Type Flanges
Lip-type flange enquiries require a drawing of the intended lip and mating arrangement. The name alone does not establish a unique connection, seal system or standard.
Construction & special designs
Puddle Flanges
A puddle flange is a collar arrangement at a pipe penetration through a wall or slab. It addresses the path around the outside of the pipe rather than a conventional bolted pipe joint.
From specification to enquiry
A connection starts with the right details.
Send your material, size, rating, facing and quantity. Include a drawing reference for non-standard requirements.
Dimensions and connection data
Define Flanges as part of the complete joint. These fields identify required engineering data; they are not universal dimensions or a declaration of available sizes.
| Parameter / designation | Technical information | Selection requirement |
|---|---|---|
| Nominal size and bore | State the nominal connection size separately from the actual bore or pipe outside diameter. | A matching size label does not establish matching internal geometry. |
| Outside diameter and thickness | Identify the finished flange diameter, minimum thickness and any hub or collar projection. | Include the drawing datum and units for replacement measurements. |
| Bolt circle and holes | Record pitch-circle diameter, hole quantity, hole diameter and any special orientation. | Check against the mating flange; do not infer a bolt pattern from pressure class alone. |
| Gasket-contact surfaces | Specify face form, seating dimensions and surface finish on the assembled joint. | Include gasket designation; a visually similar surface is not evidence of compatibility. |
| Pipe-side interface | Identify weld preparation, socket, thread, collar or other attachment geometry as applicable. | Provide pipe schedule/wall thickness and the connection-specific standard. |
| Design conditions | State design pressure, minimum/maximum temperature, fluid and mechanical loads. | Pressure class is not a pressure value in bar or psi. Use the material-specific rating basis. |
Compare related options
Compare Flanges with the related forms or references below. A related product is not necessarily a permissible substitute.
| Related product / reference | Distinction | Check before selection |
|---|---|---|
| Weld Neck Flanges | A tapered hub carries the connection from the flange body to a butt-welded pipe end. The pipe bore and wall thickness are important parts of the flange specification. | Butt-weld end; specify pipe schedule and bore |
| Slip-On Flanges | The flange bore slips over the pipe before the connection is secured with fillet welds. Pipe outside diameter and installation clearance govern the fit. | Slip-over bore with project-specified fillet welds |
| Blind Flanges | A solid flange closes a flanged opening without a through bore. Its bolted connection allows the closure to be removed for access when the system is safely isolated. | Solid centre; identify any required drilling separately |
| Threaded Flanges | Internal threads connect the flange to a matching threaded pipe end. The thread form, nominal size and mating pipe specification must be stated together. | Specify thread standard, size and engagement |
| Socket Weld Flanges | A recessed socket receives the pipe end, with a fillet weld at the outside of the hub. Socket depth, bore and assembly requirements distinguish it from a slip-on connection. | Specify socket dimensions and pipe schedule |
| Lap Joint Flanges | A backing flange works with a separate stub end or lapped pipe end. The stub end provides the gasket seating surface while the backing flange transmits the bolt load. | Specify flange and stub end as separate components |
Inspection, documents and delivery
Define acceptance requirements for Flanges in the purchase order. Required examinations and documents depend on the material, design and project specification.
| Review stage | Information to confirm | Order requirement |
|---|---|---|
| Material identity and traceability | Specification, grade, heat/lot identification and the required material certificate. | Agree documentation and marking before manufacture; visual appearance cannot verify alloy identity. |
| Dimensional verification | Critical dimensions from the selected standard or controlled drawing. | Identify inspection points, tolerances, units and drawing revision. |
| Surface and end condition | Gasket-contact surface, attachment end, edges and any coating exclusions. | State finish and visual acceptance criteria; agree protection of machined surfaces. |
| Supplementary examinations | Any specified PMI, NDE, hardness, impact, corrosion or other tests. | Define the method, sampling and acceptance criteria; tests are not automatically included. |
| Assembly compatibility | Adjoining components, weld or mechanical interface and project service conditions. | Design approval and correct assembly remain separate from a dimensional inspection report. |
| Packing and order release | Quantity, identification, surface protection, documents and delivery destination. | Agree preservation, packaging and release requirements with the order. |