| 摘要 |
<p>PURPOSE:To suppress the scale formation at the end of a steel pipe and to decrease the grazing of the steel pipe during upsetting in the stage of heating the end of steel pipe while moving the steel pipe in the diametral direction by burning a combustion gas in an induction heating furnace and the aperture part thereof and adjusting the atmosphere in the furnace. CONSTITUTION:The steel pipe 1 enters the induction heating furnace 11 through the aperture 12 thereof from the right side, moves therein while rolling toward the left and emerges from the left side. burners 13 for gas combustion are provided in each of five holes on the rear of the furnace 11 and one piece each of flame diffusion block 15 is provided to the front thereof. The flames are struck against the blocks and are thereby spread to the periphery. A burner 14 having many ejection ports is disposed in the aperture 12 fully to the width thereof and further a flow regulating box 16 is provided thereto to prevent the back flow of the combustion gas. An oxygen measuring instrument 17 is provided in the furnace and is connected to flow rate control valves 18, 19 for the combustion gas and air for combustion. While the end of the pipe 1 is heated by the furnace 11, the quantity of the oxygen in the furnace is measured by the instrument 17 and the combustion gas and the air for combustion are burned while the flow rates thereof are controlled by the valves 18, 19 so as to maintain the min. oxygen concn.</p> |
