METHOD FOR REMOVING LUBRICANT FROM HOT EXTRUSION STEEL TUBE

PURPOSE:To safely remove the glass lubricant stuck to the inner surface of steel tube in a low cost by spraying a cooling water on the inner surface of the steel tube of high temperature just after hot extruding. CONSTITUTION:The cooling water is ejected on the inner surface of a steel tube 5 just after hot extruding from a jet nozzle device 4. In this time, the steel tube 5 is rotated by a rotating device so that the cooling water can be sprayed evenly with the inner surface of steel tube, and the ejecting timing of the cooling water is executed thus, by trucking the moving position of the steel tube 5 from the preceding process, automatically opening the shutoff valve 6 when the steel tube 5 enters the prescribed cooling zone and automatically closing the shutoff valve 6 after a lapse of fixed time with the timer. If the steel tube 5 is cooled as above stated, because the steel tube is in the state of high temperature, due to the difference of the coefficient of expansion of the glass lubricant and the steel tube 5 body, the shearing force is generated at the sticking surface of the glass lubricant to the steel tube 5 body, so the glass lubricant is stripped from the steel tube 5 body. And because cooling the steel tube 5 while rotating, the distribution of temperature of the inner surface of the steel tube becomes uniform, and the steel tube is not bent.