| 摘要 |
PURPOSE:To control the temp. of a stepped shaft and to maintain the max. control temp. in the small-diameter part of said shaft within a specified upper limit range with good accuracy by measuring the actual surface temp. of the material to be heated, predicting the actual temp. under automatic control of an overall coefft. of heat transfer and setting the atmosphere temp. in a furnace. CONSTITUTION:The surface temp. of the stepped shaft which is the material 2 to be heated is measured by a radiation thermometer 7 and the result thereof is inputted to a surface temp. circuit 16 for each diameter part. The temp. output from the circuit 16 is inputted by a diameter discriminating circuit 17 to a calculation circuit 14 for predicting the temp. in the small-diameter part and a calculation circuit 15 for predicting the temp. in the large- diameter part and is also inputted to a phiCG correcting circuit 11 of the next zone. The calculating circuits 14, 15 predict and calculate the temps. in the small-diameter part and large-diameter part after the measurement of the actual temp. of the material 2. The results thereof and the target temp., quality permissible temp., etc., set in a setting circuit 12 are compared overall and the set temp. in which zone is determined by a zone set temp. determining circuit 19. The output thereof is inputted to a temp. controller 13 which compares the output and the in-furnace temp. detected by a thermometer 5 and controls a valve 20, thereby controlling the temp. in the furnace 1.
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