Lap Joint Flanges (LJ Flanges) or Loose flanges (LF flanges) called are used on piping fitted with lapped pipe or with lap joint stub ends the combined initial cost of the two items being approximately one-third higher than that of comparable welding neck flanges. Their pressure-holding ability is little, if any, better than that of slip-on flanges and the fatigue life of the assembly is only one-tenth that of welding neck flanges. The lap joint flange with the stub end assembly are normally used in systems requiring frequent dismantling for inspection and cleaning and where the ability to swivel flanges and to align bolt holes materially eases the erection of large diameter or unusually stiff piping. 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.
Lap Joint Flanges are always used with either a stub end or taft which is butt welded to the pipe with the flange loose behind it. This means the stub end or taft always makes the face. The lap joint is favoured in low pressure applications because it is easily assembled and aligned.
Lap Joint Flanges (Loose Flanges): 3/8″-80″
America Series:Class 150 ,Class 300, Class 600, Class 900A ,Class 1500,Class 2500.
Flange Facing Types
America Series:Flat face(FF),Raised face(RF),Tongue(T),Groove(G),Female(F),Male(M),Ring type joints face(RJ/RTJ)
Europe Series:Type A(Flat Face),Type B(Raised Face),Type C(Tongue),Type D(Groove),Type E(Spigot),Type F(Recess),Type G(O-Ring Spigot),Type H(O-Ring Groove)
Carbon steel: ASTM A105,ASTM A105N,GB 20,C22.8.
Alloy steel: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP 911
Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
Low temperature steel: ASTM/ASME A402 WPL 3-WPL 6
High performance steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
ASME ANSI B16.5,ASME ANSI B16.47.
API 605,API 6L.
MSS SP 44
BS1560,BS 4504,BS 10.
AFNOR NF E29-200-1
UNI 2276. UNI 2277.UNI 2278 .UNI 6089 .UNI 6090
Application for Lap Joint flange(LJ flange) /Loose flanges
Natural gas,chemical,petroleum,ship building,marine,paper making, metallurgy, electric, power, boiler , etc.
Tel No：+86-18267732328 / Email:[email protected]
Address：Longwan District, Wenzhou, Zhejiang Province, China.
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Yaang Pipe Industry Co., Ltd. is an international supplier of piping solutions for flange, butt welding fittings, socket welding fittings and threaded fittings. Our products are widely used in different industrial fields, including oil and gas, chemical industry, petrochemical industry, power plant, pulp and paper industry, environmental and water conservancy engineering, engineering projects, etc.