What is Lap Joint Flanges?
Lap Joint Flanges, also known as loose flange or split flange, are a type of flange designed to be loosely fitted onto the raised end of a vessel or pipeline.
The raised end can be formed through methods such as flanging, machining directly, or welding an additional ring. Lap joint flanges are generally categorized into two types:
Slip-on Lap Joint Flange – used in conjunction with a welding neck flange ring.
Weld Neck Lap Joint Flange – used with a flanged end.
Lap joint flanges are typically used in piping systems. Loosening the bolts allows rotation of the pipes on either side, and tightening them facilitates easier disassembly.
Advantages:
No additional moment is transferred to the vessel or pipeline if the flange warps.
Ease of manufacture.
Can be made from different materials than the vessel or pipeline, enabling cost savings on expensive metals.
Disadvantages:
Thicker flange design.
Applications:
Suitable for vessels or pipelines with brittle linings where pressure requirements are not high.
Specification
LJ Forged Flange: DN15-DN600
Surface Treatment: Anti-rust Oil, Transparent/Yellow/Black Anti-rust Paint,Zinc,Hot dipped Galvanized.
Lap Joint Flange Pressure Grade
PN0.25MPa,PN0.6MPa,PN1.0MPa,PN1.6MPa,PN2.5MPa,PN4.0MPa;
Lap Joint Flange Standards
ANSI B16.5
Male Face Steel Butt Weld Ring Lap Joint Pipe Flange with Neck: GB/T 9118.1-2000;
Ring Lap Steel Joint Pipe Flange with Neck: GB/T 9118.2-2000;
Butt Welding Lap Joint Pipe Flange: HG 20599-1997;
Flat Welding Lap Joint Pipe Flange: HG 20600-1997;
Sealing Surface Types For Lap Joint Pipe Flanges
RF (Raised Face);
FF (Flat Face);
M&F (Male-and-Female Face);
RTJ (Ring-Type Joint)
F (Female Face);
M (Male Face);
T&G (Tongue and Groove Face);
Lap Joint Flange Materials
Carbon Steel Flange: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65 ,F70;
Stainless Steel Flange: ASTM A182 F304, 304L, F316, 316L, 1Cr18Ni9Ti, 0Cr18Ni9Ti, 321, 18-8;
Alloy Steel Flange: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo, 12Cr1MoV, 15CrMo, 12Cr2Mo1, A335P22, St45.8/Ⅲ;
