Threaded flange is a kind of non-welding flange that the inner hole of the flange is processed into pipe thread and matched with the pipe with thread to achieve connection. It is compared with flat welding flange or butt welding flange, threaded flange has the characteristics of easy installation and maintenance, and can be used in some pipelines where welding is not allowed on site. Alloy steel flange has enough strength, but not easy to weld, or welding performance is not good, can also choose threaded flange.