Flange connections involve securing two pipes, fittings, or equipment to separate flange plates first, then inserting a flange gasket between the two plates and fastening them together with bolts to complete the connection. Some fittings and equipment come with a flange plate already attached, which also falls under flange connections. Flange connections are an essential method in pipeline construction. They are convenient to use and can withstand high pressure. In industrial pipelines and residential settings, where pipe diameters are small and pressure is low, flange connections are not visible. However, in boiler rooms or production sites, flange connections are abundant on pipes and equipment.

Flange connections can be categorized according to their connection methods, including: flat welding flanges, socket welding flanges, blind flanges, threaded flanges, flange covers, loose fit socket welding ring flanges, flat welding ring loose flanges, ring groove flanges, large diameter flat flanges, large diameter long neck flanges, winged blind flanges, and loose fit socket welding ring flanges, etc.