1. According to the industrial standards of chemical industry (Hg): integral flange (if), threaded flange (th), plate flat welding flange (PL), neck butt welding flange (WN), neck flat welding flange (so), socket welding flange (SW), butt welding ring loose flange (pj/se), flat welding ring loose flange (PJ /rj), lined flange cover (BL (s)), flange cover (BL).
2. According to the petrochemical (SH) industry standards: threaded flange (PT), butt welding flange (WN), flat welding flange (so), socket welding flange (SW), loose flange (LJ), flange cover (not noted).
3. According to the machinery (JB) industry standard, it is divided into: integral flange, butt welding flange, plate flat welding flange, butt welding ring plate loose flange, flat welding ring plate loose flange, flanging ring plate loose flange, flange cover.
4. According to national (GB) standards, it is divided into: integral flange, threaded flange, butt welding flange, flat welding flange with neck, socket welding flange with neck, flat welding ring loose flange with neck, plate flat welding flange, flat welding ring plate loose flange, flat welding ring plate loose flange, flanging ring plate loose flange, flange cover.