Name: Lap Joint Flange
Material: F53 (GR.2507/UNS S32750)
Standard: ASME B16.5
Size: 3″ (DN80)
A loose flange (lap joint flange) is a device that is welded onto the end of a piece of pipe to create half of a flanged coupling. Consisting of a flat steel forging with bolt holes around the perimeter and an opening in the center the size of the pipe that is intended to be welded onto the loose flange, the component can be made of carbon steel or stainless steel to meet the intended application. There are loose flange types to fit elbows, valves and nearly every type of pipeline component in use.
Due to the nature of pipelines, the connections and couplings can rarely be constructed in advance. The use of a loose flange allows a worker to create a coupling in any location along the pipeline that is feasible. The worker simply cuts the pipe at the required location and places a loose flange onto the end of the pipe. After carefully preparing the pipe to weld, the loose flange is welded permanently to the end of the pipe. If a valve or elbow is required, the worker simply welds the flange onto the elbow or valve as well as the pipe, and the union is made.
Lap Joint Flanges have all the same common dimensions as any other flange named on this page however it does not have a raised face, they used in conjunction with a “Lap Joint Stub End“.
These flanges are nearly identical to a Slip On flange with the exception of a radius at the intersection of the flange face and the bore to accommodate the flanged portion of the Stub End.
Their pressure-holding ability is little, if any, better than that of Slip On flanges and the fatigue life for the assembly is only one tenth that of Welding Neck flanges.
They may be used at all pressures and are available in a full size range. These flanges slip over the pipe, and are not welded or otherwise fastened to it. Bolting pressure is transmitted to the gasket by the pressure of the flange against the back of the pipe lap (Stub End).
Chemical Composition % of (UNS32750) 2507
Grade | Chemistry (Typical Values) | Mechanicals | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Specification | Cr | Ni | Mo | Cu | N | W | Si | Mn | P max | S max | C max | Fe | UTS N/mm² (min) | 0.20% Proof (min) | Elong % (min) | Hardness HB (max) | PREN |
2507 | 25.0 | 7.0 | 3.8 | 0.75 | 0.25 | 0.28 | 0.80 | 1.20 | 0.035 | 0.020 | 0.030 | Bal | 750 | 500-550 | 25 | 270 | 41 |
ANSI/ASME/ASA B16.5 150lb/sq.(IN). Flange – Lap Joint Flange(loose flange/LJ flange)
Pipe Size (NPS) | Outside Diameter of Flange A | Thickness of Flange C | Diameter of Bore F | Diameter of Hub at Base J | Length of Hub M | Radius | Number of Bolt Holes NBH | Diameter of Bolt Holes DBH | Bolt Circle Diameter P | Approx Weight (lb) AW |
---|---|---|---|---|---|---|---|---|---|---|
1/2 | 3 1/2 | 7/16 | 0.90 | 1 3/16 | 5/8 | 1/8 | 4 | 5/8 | 2 3/8 | 2 |
3/4 | 3 7/8 | 1/2 | 1.11 | 1 1/2 | 5/8 | 1/8 | 4 | 5/8 | 2 3/4 | 2 |
1 | 4 1/4 | 9/16 | 1.38 | 1 15/16 | 11/16 | 1/8 | 4 | 5/8 | 3 1/8 | 2 |
1 1/4 | 4 5/8 | 5/8 | 1.72 | 2 5/16 | 13/16 | 3/16 | 4 | 5/8 | 3 1/2 | 3 |
1 1/2 | 5 | 11/16 | 1.97 | 2 9/16 | 7/8 | 1/4 | 4 | 5/8 | 3 7/8 | 3 |
2 | 6 | 3/4 | 2.46 | 3 1/16 | 1 | 5/16 | 4 | 3/4 | 4 3/4 | 5 |
2 1/2 | 7 | 7/8 | 2.97 | 3 9/16 | 1 1/8 | 5/16 | 4 | 3/4 | 5 1/2 | 7 |
3 | 7 1/2 | 15/16 | 3.60 | 4 1/4 | 1 3/16 | 3/8 | 4 | 3/4 | 6 | 8 |
3 1/2 | 8 1/2 | 15/16 | 4.10 | 4 13/16 | 1 1/4 | 3/8 | 8 | 3/4 | 7 | 11 |
4 | 9 | 15/16 | 4.60 | 5 5/16 | 1 5/16 | 7/16 | 8 | 3/4 | 7 1/2 | 13 |
5 | 10 | 15/16 | 5.69 | 6 7/16 | 1 7/16 | 7/16 | 8 | 7/8 | 8 1/2 | 15 |
6 | 11 | 1 | 6.75 | 7 9/16 | 1 9/16 | 1/2 | 8 | 7/8 | 9 1/2 | 19 |
8 | 13 1/2 | 1 1/8 | 8.75 | 9 11/16 | 1 3/4 | 1/2 | 8 | 7/8 | 11 3/4 | 30 |
10 | 16 | 1 3/16 | 10.92 | 12 | 1 15/16 | 1/2 | 12 | 1 | 14 1/4 | 43 |
12 | 19 | 1 1/4 | 12.92 | 14 3/8 | 2 3/16 | 1/2 | 12 | 1 | 17 | 64 |
14 | 21 | 1 3/8 | 14.18 | 15 3/4 | 3 1/8 | 1/2 | 12 | 1 1/8 | 18 3/4 | 99 |
16 | 23 1/2 | 1 7/16 | 16.19 | 18 | 3 7/16 | 1/2 | 16 | 1 1/8 | 21 1/4 | 128 |
18 | 25 | 1 9/16 | 18.20 | 19 7/8 | 3 13/16 | 1/2 | 16 | 1 1/4 | 22 3/4 | 146 |
20 | 27 1/2 | 1 11/16 | 20.25 | 22 | 4 1/16 | 1/2 | 20 | 1 1/4 | 25 | 185 |
22 | 29 1/2 | 1 13/16 | 22.25 | 24 | 4 1/4 | 1/2 | 20 | 1 3/8 | 27 1/4 | 245 |
24 | 32 | 1 7/8 | 24.25 | 26 1/8 | 4 3/8 | 1/2 | 20 | 1 3/8 | 29 1/2 | 260 |