Classification of flanges:
1. According to the standards of the chemical industry: integral flange, thread flange, plate type plain welding flange, butt welding flange with neck, plain welding flange with neck, socket welding flange, butt welding ring loose-sleeve flange, plain welding ring loose-sleeve flange, lining flange cover, flange cover.
2. According to the petrochemical industry standard: thread flange, butt welding flange, flat welding flange, socket welding flange, loose sleeve flange, flange cover.
3. According to the mechanical industry standard: integral flange, butt welding flange, plate type flat welding flange, butt welding ring plate loose-sleeve flange, plate loose-sleeve flange, flanged ring plate loose-sleeve flange, flange cover.
4. According to national standards: integral flange, spiral flange, butt welding flange, plain welding flange with neck, socket welding flange with neck, plain welding flange with neck loose sleeve flange, plate welding flange, plain welding ring plate loose sleeve flange, plain welding ring plate loose sleeve flange, flanged ring plate loose sleeve flange, flange cover.