| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and apparatus for stably manufacturing a hot rolled steel strip with fine-grained ferrite microstructure through rolling equipment of a common specification, causing deterioration of neither thickness profile nor strip shape. SOLUTION: In the manufacturing method of the hot rolled steel strip to finish-roll such material to be rolled as a rough bar and a thin slab through a steckel mill into the hot rolled strip, heating devices and cooling devices are installed at the entry and delivery sides of the steckel mill. While the heating device heats the head and tail end parts to compensate temperature drop in those parts, the heating device at the entry side of the steckel mill rapidly heats almost the whole length of the material to a temperature not lower than Ac<SB>3</SB>during rolling and then the cooling device at the delivery side of the mill rapidly cool the material to a temperature not higher than Ar<SB>1</SB>. The rolling process is repeated for several passes and the rapid cooling is applied by the cooling device at the delivery side of the mill immediately after the final rolling pass. COPYRIGHT: (C)2004,JPO
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