LAP JOINT FLANGES are primarily employed with lap joint stubs, 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 chief use of lap joint flanges in carbon or low alloy steel piping systems is in services necessitating frequent dismantling for inspection and cleaning and where the ability to swivel flanges and to align bolt holes materially simplifies the erection of large diameter or unusually stiff piping. Their use at points where severe bending stress occurs should be avoided.
Classes 150-2500
Class 150
Class 300
Class 600
Class 900
Class 1500
Class 2500

Materials

Carbon Steel:ASTM A105, A350 LF1,LF2 CL1/CL2 LF3 CL1/CL2, ASTM A694 F42,F46,F48,F50,F52,F56,F60,F65,F70
Stainless Steel:ASTM A182 F304/304L, F316/316L, F316H,F316Ti,F321,F44(UNS S31254)
Alloy Steel:ASTM A182 F1,F5/a,F9,F11,F12,F22,F91
Duplex&Super Duplex Steel:ASTM A182 F51/UNS S31803,F53/UNS S32750 F55/UNS S3260
Special Alloy Steel:Monel400,Inconel 600, Inconel 625, Inconel 800, Inconel 825