The electric heating tube has a long service life and many protection systems, and is safe and reliable. Most combinations use argon arc welding to connect the electric heating tube to the flange. The fasteners can also be in the form of fastening devices, that is, each electric heating tube is welded to the fastener, the nut and the flange cover are fastened, the pipe and the The fasteners are argon arc welded. Do not leak. The sealing part of the fastener adopts science and technology, and it is very convenient to replace the single piece, which greatly saves the future maintenance cost. Compared with ordinary metal heaters, it has stable electrical performance, high thermal efficiency, energy saving of more than 30%, and fast heating.