| 摘要 |
PURPOSE:To reduce a time of pickling and to improve a consumption unit of pickling liquid, by pickling a hot rolled sheet of low carbon steel after cold- rolling the sheet in a range of a specified draft while jetting a specified quantity of water for cooling and lubricating. CONSTITUTION:A hot rolled sheet of low carbon steel is cold-rolled in 5- 30% draft while jetting water for cooling and lubricating at the rate of 0.3- 3l/min./mm. of the sheet width. The draft is regulated in the above-mentioned range, because an exfoliative effect is insufficient when rolled in a <=5% draft and the effect becomes saturated in a >=30% draft. The jetting flow rate of water for cooling and lubricating is regulated in the above-mentioned range, because of an insufficient cooling which causes heat scratchs when he water is jetted at the flow rate of <=0.1l/min./mm. sheet width, and the occurrence of the heat scratch is prevented when the water is jetted at the rate of <=3l/min./ mm. sheet width, even if the cold rolling speed is made faster. Next, the pickling is performed, and also the running speed of the sheet in the pickling bath is made faster. |
