Lap Joint Flange

A Lap Joint Flange is a type of pipe flange comprising two parts: a flat, circular disc (the “stub end”) and a ring or hub (the “lap joint”). The stub end is typically welded to the pipe or fitting, while the lap joint rotates freely around it. This design facilitates easy alignment during assembly.

These flanges are commonly used in piping systems where frequent dismantling and reassembly are necessary, such as those handling corrosive or abrasive fluids or in systems with thermal expansion considerations. They offer versatility, allowing for adjustments and disassembly without disturbing the entire piping system.

Lap joint flanges come in various materials, sizes, and facings to suit different applications and operating conditions. They are available with flat face (FF), raised face (RF), or ring type joint (RTJ) facings, depending on sealing requirements.

Material Grades

Stainless Steel: ASTM / ASME SA403 GR WP “S” / “W” / “WX” 304, 304L, 304H, 309, 310H, 316L, 316H, 317, 317L, 321, 321H, 904, 904L, 347, 347H.

Duplex Steel: ASTM / ASME SA815 UNS NO. S31803, S32205, S32550, S32750, S32760.

Carbon Steel: ASTM / ASME A234 WPB, WPC, ASTM / ASME A860 WHY42, WHY46, WHY52, WH60, WPHY65 & WPHY70

Alloy Steel : ASTM / ASME A234 WP1, WP5, WP9, WP11, WP 12, WP22, WP23, WP91