A lap joint flange (LJF) is an assembly of two elements involving a stub end and a lap joint ring flange (also called a ‘lap joint flange’). To be technically correct, the stub end is not part of a lap joint flange. However, a lap joint flange is always used in conjunction with a stub end, so both parts are often collectively referred to as a ‘lap joint flange’.
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details of socket lap joint flange: 1. lap joint flange; 2. stub end; 3. butt weld; 4. pipe or fitting; 5. radiu |
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Due to their design, lap joint flanges always have a flat face with a smooth surface. But, when combined with the stub end, the resulting sealing face is raised. This occurs because the sealing face of the stub end is above the flange’s bolting plane.
The lap joint flange has no sealing face, only the stub end has the sealing face.
The sealing face of a stub end may be plain, serrated, or grooved to allow for a ring type joint.
Lap joint flanges are available in many sizes and classes; they are also suitable for elevated temperatures and pressures. Generally, a lap joint flange can be used for the same applications as a welding neck flange.
To assemble a lap joint ring flange and stub end, the stub end must slide into the bore of the flange ring and then be butt welded to the pipe. One side of the stub end forms the sealing face, whilst the opposite/back side of the stub end presses against the lap joint flange ring (when the flange is assembled). The lap joint flange ring is free to rotate after the stub end is welded to the pipe, this is because it is not physically joined to the stub end. Once the flange joint has been assembled, the lap joint ring is no longer free to rotate.
The advantages with the lap joint flange design are:
Inexpensive.
Well suited for corrosive applications.
Requires only a single full penetration butt weld.
Only the stub end has contact with the process medium
It can be easily adjusted to align with the mating flange (the flange can be rotated until the bolt holes align).
It is available in almost all pipe diameters.
Ideal for systems where frequent disassembly of the flange is required e.g. when cleaning or inspection is required.
It is possible to use a cheaper grade material for the lap joint flange e.g. carbon steel, because only the stub end must match the associated pipe material/grade; this can result in considerable cost savings.
There are some limitations on the lap joint flange’s usage, mostly due to its bulkier multiple component design. Lap joint flanges cannot be used for small size piping.
Non-Destructive Testing (NDT) Techniques
Magnetic particle inspection (MPI), dye penetrant inspection (DPI), radiographic testing (RT) and/or ultrasonic testing (UT), can be used to prove the butt weld (same techniques as used for a welding neck flange).
ASME Standards
Dimensions and tolerances for lap joint flange stub ends are outlined in the ASME B16.9 standard. Note, this differs from the usual ASME B16.5 standard because a stub end is classified as a pipe fitting, not a flange.
Standard Specification For Lap Joint Flanges
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Dimensions |
ANSI B16.5, ANSI B16.47 Series A & B, MSS SP44, ASA, API-605, AWWA, Custom Drawings |
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Size |
1/2" (15 NB) to 48" (1200NB) |
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Class |
150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS, DIN Standard ND-6,10, 16, 25, 40 Etc. |
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DIN |
DIN2527, DIN2566, DIN2573, DIN2576, DIN2641, DIN2642, DIN2655, DIN2656, DIN2627, DIN2628, DIN2629, DIN 2631, DIN2632, DIN2633, DIN2634, DIN2635, DIN2636,DIN2637, DIN2638, DIN2673 |
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BS |
BS4504 , BS4504, BS1560, BS10 |
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Flange Face Type |
Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ) |
Material & Grades of Lap Joint Flanges
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Stainless Steel Lap Joint Flanges |
ASTM A 182, A 240 F 304, 304L, 304H, 316, 316L, 316Ti, 310, 310S, 321, 321H, 317, 347, 347H, 904L |
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Duplex & Super Duplex Steel Lap Joint Flanges |
ASTM / ASME A/SA 182 F 44, F 45, F51, F 53, F 55, F 60, F 61 |
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Carbon Steel Slip Lap Joint Flanges |
ASTM / ASME A/SA 105 ASTM / ASME A 350 , ASTM A 181 LF 2 / A516 Gr.70 A36, A694 F42, F46, F52, F60, F65, F706 |
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Low Temperature Carbon Steel Lap Joint Flanges |
ASTM A350, LF2, LF3 |
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Alloy Steel Lap Joint Flanges |
ASTM / ASME A/SA 182 & A 387 F1, F5, F9, F11, F12, F22, F91 |
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Copper Alloy Steel Lap Joint Flanges |
ASTM SB 61 , SB62 , SB151 , SB152 UNS No. C 70600 (Cu-Ni 90/10), C 71500 (Cu-Ni 70/30), UNS No. C 10100, 10200, 10300, 10800, 12000, 12200 |
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Nickel Alloy Lap Joint Flanges |
ASTM SB564, SB160, SB472, SB162 Nickel 200 (UNS No. N02200), Nickel 201 (UNS No. N02201), Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500), Inconel 800 (UNS No. N08800), Inconel 825 (UNS No. N08825), Inconel 600 (UNS No. N06600), Inconel 625 (UNS No. N06625), Inconel 601 (UNS No. N06601), Hastelloy C 276 (UNS No. N10276), Alloy 20 (UNS No. N08020) |
ASME B16.5 Raised Faced Lap Joint Flanges Available Types
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Lap Joint Flange |
Lapped Joint Flanges |
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ANSI B16.5 Lap Joint Flanges |
Lap Joint Flange Dimensions |
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ASME B16.5 Lapped Joint Flanges |
ANSI B16.5 Class 150 Lap Joint Flanges |
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Stainless Steel Lap Joint Flanges Suppliers |
SS Lap Joint Flange |
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Lapped Joint Plate Flanges Dealer |
ASME B16.47 Series A and B Lap Joint Flanges Exporter |
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ANSI B16.5 class 150 Lap Joint Flange Stockholder |
ANSI 150 Lap Joint Flange Distributors |
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Carbon Steel Lap Joint Flange |
High Quality Lap Joint Flanges Manufacturer |
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ASTM A182 Stainless Steel Lap Joint Flange |
Duplex Steel Lapped Joint Flange |
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Super Duplex Steel Lap Joint Forged Flange |
Copper Nickel Lap Joint Pipe Flanges |
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High Nickel Alloy Lapped Joint Flanges |
Hastelloy Flat Faced Lap Joint Flanges Stockist |
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Titanium ASME B16.47 Series A and B Lap Joint Flanges |
Inconel Lap Joint Flanges |
ANSI B16.5 Lap Joint Flanges Application
ASME B16.5 Lap Joint Flanges are known to deliver exceptional performance and are generally developed for meeting the demands. We offer a broad range of Lapped Joint Flanges through a worldwide network of stock-keeping branches. These Lap Joint Flange is use in various industries like :
Stainless Steel Lap Joint Flanges uses in Oil and Gas Pipeline
Lap Joint Flanges uses in Chemical Industry
Alloy Steel Lap Joint Flanges uses in Plumbing
Flat Faced Lap Joint Flanges uses in Heating
Lap Joint Pipe Flanges uses in Water Supply Systems
ANSI B16.5 Lap Joint Forged Flanges uses in Power Plant
Lapped Joint Plate Flanges uses in Paper & Pulp Industry
Lap Joint Flange uses in General Purpose Applications
Steel Lap Joint Flanges uses in Fabrication Industry
Lapped Joint Flange uses in Food Processing Industry
Lap Joint Flanges uses in Structural Pipe
