04 // Industrial Flanges

Lap Joint Flanges

VEFLOX manufactures premium Lap Joint Flanges designed for complex piping systems requiring frequent dismantling and exotic materials. Used in conjunction with a corresponding stub end, this two-part assembly allows the flange to rotate freely over the pipe, ensuring effortless bolt alignment while completely isolating the flange from the corrosive fluid inside the pipeline.

Unrestricted Bolt Alignment

Detailed Technical Specifications

Flange Profile

Lap Joint (LJ): Similar to a Slip-On flange, but features a machined radius at the intersection of the bore and the flange face to perfectly accommodate the flared portion of a Pipe Stub End.

Dimensional Standards

ASME/ANSI B16.5 (1/2" to 24"), EN 1092-1, DIN 2641/2642, BS 4504, JIS B2220

Pressure Ratings (Class)

ASME/ANSI: 150#, 300#, 600#, 900#, 1500#, 2500#
DIN/EN: PN6, PN10, PN16, PN25, PN40

Material Grades

Carbon Steel: ASTM A105 / A105N, A350 LF2 / LF3 (Most common for cost-saving applications).
Stainless Steel: ASTM A182 F304/304L, F316/316L, F321
Alloy & Low Temp: ASTM A182 F11, F22, A350 LF2

Facing Types

Flat Face (FF). The Lap Joint Flange itself is flat; the required raised gasket surface is provided by the mating Stub End.

Bore Tolerances

Machined slightly larger than the connecting pipe's Outer Diameter (OD) to allow the flange to slide freely over the pipe before the stub end is welded.

Assembly Protocol

The flange is slipped over the pipe, the stub end is butt-welded to the pipe end, and the flange is then pulled forward to seat against the back of the stub end.

Core Advantages

Drastic Material Cost Reduction

Because the flange never touches the fluid, you can weld an expensive exotic alloy stub end to the pipe while using a highly economical carbon steel Lap Joint Flange for the bolted connection.

Instant Bolt Hole Alignment

The backing flange remains completely unattached from the pipe. This allows it to rotate 360 degrees, making it incredibly easy to align bolt holes with mating flanges during installation.

Salvageable Component

Since it is not welded directly to the pipeline, the Lap Joint Flange can often be salvaged and reused when a piping system is dismantled or decommissioned.

Industries Served

Oil & Gas

Petrochemicals

Power Generation

Water Treatment

Shipbuilding

Pharmaceuticals