Butt welding flanges flanges: neck is often referred to as "high hub" flange. Its purpose is to transfer pressure pipe, thus reducing the flange base high stress. Neck welding flanges are the best design butt those currently because its itself exists structural value provide flange. This is expensive, because design. Threaded (threaded) flange: this thread flange similar to sliding flange, but hole threads. Its main advantage is that it can not welding assembly, in ordinary explain atmospheric temperature at low use of the service and highly explosive areas, creating a dangerous welding. Slide on the sliding flanges flanges: has lower hub, because pipeline into single before welding flanges. This is the internal and external welding provide sufficient strength, prevent leakage. Sliding flange, are boring slightly larger diameter pipe matching. They are superior to the welding, due to neck flange initial cost is low, and many users, but in the end the cost of the installation of probably won't, because that increase than the soldering welding neck flange less. Lap lap flanges flanges: in fact is identical sliding flange, unless it in the hole and flange race among a radius. This is the necessary radius flange accommodate lap stub ended. Usually, lap flange and lap stub end together assembly system mating. This socket weld flange is a similar sliding flange, unless it has a hole and the holes. Counter hole slightly more beer than O.D. pipe matching, make the pipeline inserted into the flange similar sliding flange. In smaller hole diameter is the same ID the same pipeline matching. Restrictions are built-in hole, as a specially designed for pipeline shoulder covers stay at the bottom. This eliminates any traffic limit in use socket welding flanges.