weld neck reducing flange 1.size: 3/8 ... 304,316L,321 3.standard:HG20592, ASME16.5B, weld neck reducing flange 1.size: 3/8''~160''. ... -welded Flange (SW), Slip-on Flange (SO), Welding-Neck Flange (WN), Threaded Flange (TH), etc.American SeriesCLASS ... weld neck flanges, socket weld flanges, lap joint flanges, spectacles flanges, ring joint flanges, orifice flanges, long weld neck flanges etc. Weld Neck ...