GOST 12820-80 FLANGE tells you that flanges are made of the following materials. Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, chrome molybdenum steel, chrome molybdenum vanadium steel, molybdenum titanium, rubber-lined, fluorine-lined material. GOST 12820-80 FLANGE tells you that flanges are classified as follows. Flat welding flanges, neck flanges, butt welding flanges, ring connection flanges, socket flanges, blind plates, etc.

GOST 12820-80 FLANGE tells you that the implementation standards of flanges are as follows. There are GB series (National Standard), JB series (Department of Machinery), HG series (Ministry of Chemical Industry), ASME B16.5 (American Standard ), BS4504 (British Standard), DIN (German Standard), JIS (Japanese Standard).
GOST 12820-80 FLANGE tells you that the international pipe flange standard system has the following types. There are two main international pipe flange standards, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by American ANSI pipe flanges.
The above information is the GOST 12820-80 FLANGE manufacturer's introduction and analysis of the knowledge of the flange, hope it helps you.