Lap Join Flange
What is Lap Joint Flange?
Lap Joint Pipe Flanges slide over the pipe and are most commonly used with Stub End Fittings. A pipe is typically welded to the Stub End and the Lap Joint pipe flange is free to rotate around the stub end. The benefit of this is that there will not be any issues with bolt hole alignment. Lap Joint pipe flanges are often used for applications that require frequent dismantling. Slip on Pipe flanges with a hub has published specifications that range from 1/2" thru 24". Sizes above 24" are produced as lap joints to slip on dimensions. Coastal Flange provides Lap Joint pipe flanges in all material grades, specifications and sizes.
Lap Joint Flanges are similar to other types of industrial flanges, but it does not have a raised face. Lap joint flanges are used in conjunction with a “Lap Joint Stub End”. The total initial cost of a lap joint flange along with a stub end is around one-third higher than that of comparable welding neck flanges. The pressure holding capacity of lap joint flanges is comparatively lower, and the fatigue life for the assembly is only one tenth that of welding neck flanges.We are an ISO 9001:2008,ISO 9001-2008, ISO 14001-2004, OHSAS 18001-2007, NSIC-CRISIL, EEPC, and QA-UKAS (ISO 9001-2008), SSI Certified company that follows total Quality Management System. and have been recognized as one of the world’s leading stockists and manufacturer of quality metals for over two decades and are committed to quick responses, unsurpassed quality, competitive pricing, reliable deliveries and an exhaustive inventory.
Lap Joint Flanges Specification
| Type | Socket Weld Flange |
| Standards | ANSI B16.5, ANSI B16.47 Series A & B, MSS SP44, ASA, API-605, AWWA, Custom Drawings |
| Outside Diameter | ≤ 24 = 1.6 mm > 24 = ± 3.2 mm |
| Inside Diameter | ≤ 10 = ± 0.8 mm > 12 = + 1.6 mm / - 0 mm |
| Diameter Contact Face | 1.6 mm RF = ±0.8 mm 6.35 mm RF = ±0.4 mm Tongue & Groove = ±0.4 mm Male-Female = ±0.4 mm |
| Outside Diameter of Hub | ≤12 = + 2.4 mm/ - 1.6 mm ≥ 14 = ± 3.2 mm |
| Diameter of Counterbore | Same as for Inside Diameter |
| Drilling | Bolt Circle = 1.6 mm Bolt Hole Spacing = ±0.8 mm Eccentricity Bolt Circle with Respect to Facing ≤2.1/2 = 0.8 mm max ≥3 = 1.6 mm max |
| Thickness | ≤18 = +3.2 mm / -0 ≥20 = +4.8 mm / -0 |
| Length thru Hub | ≤18 = 3.2 mm / - 0.8 mm ≥20 = + 4.8 mm / - 1.6 mm |
| Pressure Ratings: | Class 150, Class 300, Class 400, Class 600, Class 900, Class1500, Class 2500 | PN6, PN10, PN16, PN25, PN40, PN64 etc. |
| Order | Accept custom order |
| Quality Assurance | All fittings and flanges are subject to strict inspection at each stage of the production process, from starting material purchasing to product dispatch. They are visually examined for conformity to ASTM, ASME, MSS, DIN, EN, and JIS codes and standards. Upon request, official certified Inspection Agencies can be called in to witness the material reports, dimensions and quality conformity of products. |
| Marking & Packing | Products are packaged to ensure that there is no damage during transit. In case of exports, standard export packaging is done in wooden cases. All buttweld fittings are marked with Grade, Lot No, Size, Degree and our trade mark. On special requests we can also, make custom marking on our products.#Protected by End Caps. |
| Value Added Services |
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| Test Certificates | Manufacturer Test Certificate as per EN 10204 / 3.1B, Raw Materials Certificate, 100% Radiography Test Report, Third Party Inspection Report |
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).
Lap Joint flanges have certain special advantages:
- Freedom to swivel around the pipe facilitates the lining up of opposing flange bolt holes.
- Lack of contact with the fluid in the pipe often permits the use of inexpensive carbon steel flanges with corrosion resistant pipe.
- In systems which erode or corrode quickly, the flanges may be salvaged for re-use.
| Carbon Steel Lap Joint Flanges: | ASTM A105/A105N, A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, A694 F42, F46, F48, F50, F52, F56, F60, F65, F70, A516.60, 65, 70 (Spectacle Blind Flange, Spacer Ring/Spade Flange), Steel RST37.2, C22.8 |
| Stainless Steel Lap Joint Flanges: | ASTM A182 F202, F304/304L/304H, F316/316L, F316H, F316TI, F310, F321, F904L |
| Alloy Steel Lap Joint Flanges: | ASTM A182 F1, F5, F9, F11, F22, F91 |
| Special Alloy Lap Joint Flanges: | Duplex, Super Duplex, Nickel Alloys |
| Flange Face Type: | Weld neck Flate Face (WNFF), Weld neck Raised Face (WNRF), Weld neck Ring Type Joint (WNRTJ) |
| Coating/Surface Treatment: | Anti-rust Paint, Oil Black Paint, Yellow Transparent, Zinc Plated, Cold and Hot Dip Galvanized |