A flange is a component that connects shafts to each other, used for connecting pipe ends; there are also flanges used at equipment inlets and outlets, such as reducer flanges, for connecting two pieces of equipment. Flange connection or flange joint refers to a removable connection consisting of a flange, a gasket, and bolts, all interconnected to form a combined sealing structure. Pipe flanges refer to flanges used for piping in pipeline installations; when used on equipment, they refer to the equipment's inlet and outlet flanges. Flanges have holes, and bolts secure the two flanges together. Gaskets are used to seal between the flanges.

The connection process involves securing two pipes, fittings, or equipment to separate flanges, inserting a flange gasket between them, and then tightening them together with bolts to complete the connection. Some fittings and equipment come with their own flanges and are also considered flanged connections. Flanged connections are an important method in pipeline construction. They are convenient to use and can withstand high pressure. In industrial pipelines and residential settings, where the pipe diameter is small and the pressure is low, flanged connections are not visible. However, in boiler rooms or production sites, you will find pipes and equipment connected with flanges everywhere.