... flange, slip-on flange (SO), socket welding flange, lap joint flange (LJF), welding neck flange (WNF), blind flange, orifice flange, reducing flange, pad type flange, loose hubbed flange, welding plate flange ... , DIN2527, DIN2631, 2632, 2633, 2634, 2635,KS B1502, JIS B2203, KS B1503, JIS B2220, JIS B2216Usage: connecting pipe line and keep its leakproofness ...