item name:crew thread flange(thread flanges, pipe) Carbon Steel:ASTM A105,20# ... A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2AS item name: crew thread flange(thread flanges, pipe)Seal Cover:FFRFMFMTGRJMaterial: Carbon Steel ... ,ANSI B16.5HG20622-1997GB/T9123.1-2000GB/T9123.4-2000 crew thread flange(thread flanges)