... steel standards:ANSI,GB,ASME,DIN,EN etc. WN flange/welding neck flange/carbon steel flange/pipe fitting Quality guaranteed,favourable ... , DIN2636, DIN2637, DIN2638, DIN2673 B.S. flangeBS 4504 SEC 3.1: WELDING NECK FLANGE(111/134), HUBBED SLIP ON FLANGE(112), HUBBED ... THREADED FLANGE(113), LAPPED PIPE END FLANGE(133), PLATE FLANGE(101 ...