The slip-on flange has a low hub because the pipe slips into the flange prior to welding. It is welded both inside and out to provide sufficient strength and prevent leakage. Slip-on flanges are all bored slightly larger that the O. D. Of the matching pipe. They are preferred over welding neck flanges by many users due to their lower initial cost, but final installation cost is probably not much less than that of the welding neck flange because of the additional welding involved.
Slip-on Flange for Oil Fields, Made of A350 LF2 Material
Materials:
Type: welding neck, slip-on, threaded, lap joint, socket welding, and blind
Manufacturing standards: API, ANSI, BS, JIS, UNI, MSS, and SP
Pressure: ANSI class 150 to 2,500
Size range: 1/2 to 56 inches (DN15 to DN1,400mm)
Slip-on Flange for Oil Fields, Made of A350 LF2 Material
ASTM A105
A350 LF1, LF2 CL1/CL2, and LF3 CL1/CL2
A516.60
A694 (F42, F46, F48, F50, F52, F56, F60, F65, and F70)
A182 F304/304L, F316/316L, F316H, F310, and F321
A182 F11 and F22