Carbon steel butt welding flange is a kind of pipe fitting, refers to the flange with a neck and a circular pipe transition and butt welding connection with the pipe.Butt welding flange is a kind of disc parts, are the most common in the pipeline engineering, flanges are used in pairs. In pipeline engineering, is mainly used for pipe butt welding flanges. In need of connecting pipes and all kinds of installation of a flange, the low pressure pipe flange can use silk, the use of more than 4 kg pressure welding flange. Add seal between two pieces of flange, bolt. Then different stress of flange bolts with different thickness and use different., pump and valve in and pipeline connection, these local equipment, also made the corresponding flange shape, also known as flange connection.