Threaded-type electric-heating tube: male electrothermal tube structure of tubular electric heating element is a metal tube in the heating element, partially filled with close the gap and have good thermal conductivity and crystallization of magnesium oxide insulation. Hexagonal threaded flange heaters from flat flange type electric heating tube is threaded nipple, threaded pipe thread, with 6 points, 1-inch, 1.2 inch, 1.5 inch, and so on.