| 摘要 |
PROBLEM TO BE SOLVED: To provide a temperature control method by which in a heating furnace used for producing a steel forged product, desired temperature in the furnace over the wide temperature range such as 200-1,000°C is obtained and is easily and accurately held. SOLUTION: Heating is performed by installing, in a single-chamber furnace, a burner in which a second air nozzle (2) is disposed around a combustion nozzle (1) of a gas burner, the gas burner mixing primary air into fuel gas and spouting the fuel gas from the combustion nozzle (1), and having the ratio of air/fuel changeable in the wide range. In the case of rising the temperature in the furnace from the low temperature range into the middle temperature range, and in the case of performing slow-cooling, the ratio of air/fuel gas in the primary air is selected to high and also, the air is blown from the secondary air nozzle, and the ratio of air/fuel gas of the total of the primary and the secondary air nozzles is made higher. In the method, the heating of a blank before forging and the slow-cooling for passing through a transformation point and an annealing, can be performed with the single furnace. COPYRIGHT: (C)2006,JPO&NCIPI
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