| 摘要 |
PURPOSE:To ensure uniform quality by providing plural heat exchangers in a heat treatment furnace in the direction of width of the furnace in the part where the low temperature zone and high temperature zone are adjoining, and thereby cooling the whole at uniform rate irrespective of difference in thickness of each part of heat treated object. CONSTITUTION:A cast iron tube M carried from the inlet 4 of a heat treatment furnace used for annealing of case iron tube etc. is cementite decomposed and pearlite decomposed while it passes through the high temperature and low temperature zones 6, 7. There is no perfect partition between the temperature zones 6, 7 except a projected wall 9. Since plural number 10a-10e of heat exchangers are provided in the direction of width of the furnace, the gas in the furnace is quenched by heat changing action of the exchangers. The temperature of the temperature zone 7 is made to specified temperature in a short moving distance from the temperature zone 6. The flow rate of heat medium of each heat exchanger is set according to the shape of each part of the tube M, and the flow rate of heat exchanger 10a at the position of passing of the thick faucet (m) of the tube M is made greater than the other. Accordingly, the faucet (m) is cooled at the same rate with other parts. |
