Bronze Lap Joint Flanges Manufacturer & Exporter
A lap joint flange is a loose flange used together with a stub end. The flange rotates freely on the pipe, which simplifies bolt-hole alignment during assembly.
What is a Lap Joint flange?
The lap joint assembly consists of a stub end, welded or brazed to the pipe, and a lap joint flange that sits behind the stub end’s lap. The stub end forms the sealing face; the flange only applies bolt load. Because the flange is not fixed to the pipe, it can be rotated to line up bolt holes, which is valuable on systems that are dismantled often or where pipe spools must be fitted to fixed nozzles.
A further advantage is material flexibility: the stub end can be in the pipe material while the flange is bronze, or vice versa, and a cheaper material can be used where the flange does not touch the medium — subject to galvanic and design considerations.
Construction
- Bore sized to pass over the pipe, with a radiused or chamfered corner to seat the stub-end lap
- Flat back face for bolt-load seating
- Bolt holes drilled to specified pattern
- Face dimensions compatible with the stub end
- Thickness per standard or design
Values vary according to applicable specification, material condition and customer requirements.
Bronze Lap Joint Flanges — specification
| Type | Lap joint (loose, rotating) flange used with a stub end |
|---|---|
| Bore corner | Radius or chamfer to suit stub end |
| Facing | Back face for bolt load; sealing at the stub end |
| Pressure class | As defined by the applicable standard |
| Sizes | As per customer requirement / applicable standard |
| Pressure classes | Pressure classes and pressure-temperature ratings are defined by the standard applied and depend on alloy and temperature. Available as per applicable material and dimensional standard. |
| Facing options | Flat face (FF), raised face (RF) or custom facing as specified by the standard or drawing. |
| Standards | Typical reference standards for copper-alloy flanges include ASME B16.24 (cast copper alloy pipe flanges and flanged fittings), MSS SP-106 (cast copper alloy flanges and flanged fittings) and EN 1092-3 (copper alloy flanges). Customer drawings and other national or project standards are also worked to. The standard to be applied is confirmed when the enquiry is reviewed. |
|---|---|
| Dimensions | Outside diameter, thickness, bore, bolt-circle diameter, number and size of holes per the standard or customer drawing. Available as per applicable material and dimensional standard. |
Available bronze materials
Available as per applicable material and dimensional standard. Select a grade for composition limits, mechanical properties and corrosion notes.
| UNS grade | Alloy family | Note |
|---|---|---|
| UNS C95800 | Nickel aluminium bronze, NAB (Cu-Al-Ni-Fe-Mn) | UNS C95800 is the standard cast nickel aluminium bronze for seawater service. |
| UNS C95400 | Aluminium bronze (Cu-Al-Fe) | UNS C95400 is a heat-treatable aluminium bronze that combines high strength with good wear and corrosion performance, making it a common choice for demanding pump, valve and marine components. |
| UNS C83600 | Leaded red brass / composition bronze (Cu-Sn-Pb-Zn) | UNS C83600 — commonly called gunmetal, composition bronze or red bronze — is the traditional general-purpose cast alloy for valves, pump parts and pipe fittings, and the material behind our gunmetal flanges. |
| UNS C93200 | Leaded tin bronze (Cu-Sn-Pb-Zn) | UNS C93200 is a leaded tin bronze widely used where free machining, good pressure tightness in castings and bearing behaviour matter more than very high strength. |
Where these flanges are used
- Systems that are frequently dismantled
- Pipework where bolt-hole alignment is difficult
- Piping with dissimilar flange and pipe materials
- Marine and process piping with stub ends
See also: Marine · Shipbuilding · Industrial Piping.
Inspection and testing
- Bore radius or chamfer against stub-end lap
- Flange thickness and outside diameter
- Back-face flatness
- Hole pattern (PCD) and bolt-hole size
- Material identification and documents as agreed (MTC, inspection report, as applicable)
Made to your specification
Stub-end compatibility is critical: please supply the stub-end drawing or standard along with the flange requirement.
For non-standard dimensions, see custom & special flanges.
Related flange types
- Loose FlangesLoose flanges are not fixed to the pipe.
- Slip-On FlangesSlip-on flanges are machined from bronze and copper-alloy grades so that the pipe slides into the bore and is secured by fillet welding or brazing, depending on material and procedure..
- Socket-Weld FlangesSocket-weld flanges have a recess into which the pipe is inserted.
Have a Bronze Flange Requirement?
Send us your drawing, specification, material grade, size and quantity.