Flange connections involve securing two pipes, fittings, or equipment to separate flange discs first, then inserting a flange gasket between them and tightening them together with bolts, thereby completing the connection. Some fittings and equipment come with flange discs already attached, which also fall under flange connections. Flange connections are an essential method for pipeline construction. They are convenient to use and can withstand high pressure. In industrial pipelines and within homes, where the pipe diameters are small and the pressure is low, flange connections are not visible. However, in boiler rooms or production sites, flanged pipes and equipment are abundant.

Flange connections can be categorized by type of connection as: flat welding flanges, socket welding flanges, blind flanges, threaded flanges, blind flange covers, ring-type joint flanges, loose ring flanges, face-to-face flanges, large diameter flat flanges, large diameter long-neck flanges, L-shaped blind flanges, and loose ring face-to-face flanges, etc.