Roller preheating and heat-insulation system

The invention discloses a roller preheating and heat-insulation system which comprises an oil tank, a circulation pump, a heater, a cooler, an upper roller, a lower roller and a controller, wherein oil cavities are formed inside the upper roller and inside the lower roller respectively, and a temperature sensor is arranged on an oil inlet pipeline of the heater. According to the roller preheating and heat-insulation system, hot oil is conveyed to the rollers to pre-heat the rollers before rolling, and therefore rolling cracks generated when a magnesium alloy sheet is in contact with a low-temperature roller are avoided; meanwhile, in the rolling process, the controller controls the heater and the cooler to adjust the oil temperature to enable the temperature of the rollers to be kept within a temperature range required by the technique, therefore, the problem that due to the fact that the temperature of the rollers is high and high heat generated in the rolling process can not be taken away in time, overburning, increasing of the size of crystalline grains and reduction of the mechanical property of the magnesium alloy sheet are avoided, and the problem that due to the fact that the temperature inside the rollers is low, the temperature of a rolled piece is absorbed by the rollers, and then the rolling cracks are generated is solved.