Threaded flanges use threads such as the 55 ° conical internal thread Rc specified in GB 7306, the 55 ° cylindrical internal thread RP specified in GB 7306, and the 60 ° conical internal thread NPT specified in GB/T 12716 (in addition, PT, also known as BSPT, is a 55 ° sealed conical pipe thread, belonging to the Wyeth thread family, mostly used in Europe and Commonwealth countries, commonly used in the water and fecal gas pipe industry, with a taper of 1:16, the national standard GB/T7306-2000, known as ZG domestically; ZG conical pipe thread, ZG is the old code, R is the outer thread of the conical pipe, and Rc is the conical internal thread); G is a 55 ° non threaded sealing pipe thread, belonging to the Wyeth thread family. The symbol G represents cylindrical thread. The national standard can be found in GB/T7307-2001.

Threaded flanges do not belong to high-pressure flanges and are suitable for low pressure applications such as engineering construction, air conditioning water systems, etc. They can be safely used. Threaded flange is a commonly known type of threaded product, such as the pipe fittings used for household tap water. It is commonly used in engineering construction and has the advantages of easy on-site installation, convenient maintenance, and no need for welding. It can be used on pipelines that do not allow welding, are difficult to weld, or have poor welding performance. Threaded flanges do not belong to high-pressure flanges. Standard threaded flanges are neck flanges. Except for the flange inside, other sizes of neck flat welding flanges and socket welding flanges are the same. One end of the threaded flange is connected to the pipeline thread, and the other end is connected to other flanges, flange covers, equipment, valves, etc.

The sealing surface of threaded flanges is only available in two types: full flat and protruding. In China, threaded flanges are only suitable for the British pipe series. The threaded processing of the inner hole pipe of the threaded flange should ensure that the end of the steel pipe after tightening is close to but not beyond the sealing surface of the flange. When using the 60 degree conical pipe thread specified in GB/T12716 for threaded flanges, the outer diameter of the steel pipe used for DN65 flanges should be 73mm; the outer diameter of the steel pipe used for DN125 flanges should be 141.3mm. When using the 55 degree pipe thread specified in GB7306, the outer diameter of the steel pipe used for DN150 flanges should be 165.1mm.

Threaded flange is a non welded flange that processes the inner hole of the flange into a pipe thread and connects it with a threaded pipe. Considering the structural characteristics of threaded flanges, they are not suitable for flammable, explosive, and hazardous environments. Threaded flanges are suitable for pressures ranging from 0.6-4.0Mpa and diameters of DN10-DN150. Threaded flanges have the same dimensions as neck welding flanges, except for the inner diameter thread size.