| 摘要 |
PURPOSE:To control easily and surely the size of a PC steel bar in a production line for said bar by controlling the temp. of the bar in accordance with the temp. in gas firing furnaces and the speed of the steel bar in hardening and tempering stages and controlling the tension on the bar from the size thereof after hardening. CONSTITUTION:A hardening furnace 6 and a tempering furnace 8 which are gas firing furnaces in a heat treating stage for a production line for a PC steel bar are controlled to maintain a steel bar 1 at a prescribed temp. by means of thermocouples 24 and gas and air control valves 20, 21. The temp. of the bar 1 in the outlets of the furnaces 6, 8 is actually measured with a thermometer 25, and variable speed motors 31, 26 for driving a drawing machine 5 with irregular shape working and a takeoff 10 respectively by which the line speed is controlled. The tension on the bar 1 is controlled at the same instant by measuring actually the size of the bar 1 after hardening in the outlet of a water tank 7 for hardening with a wire diameter measuring device 30, and controlling the motor 26 in accordance with the measured value, by which the wire diameter of the bar 1 is controlled constant. |
