... ,20Mn,304,316L,321 3.standard:HG20592, ASME16.5B, weld neck reducing flange 1.size: 3/8''~160''. 2. ... plate flanges, screwed flanges, blind flanges, reducing flanges, weld neck flanges, socket weld flanges, lap joint flanges, spectacles flanges, ring joint ... flanges, orifice flanges, long weld neck flanges etc. Weld Neck Flange ...