| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot-rolled steel strip capable of producing a cold-rolled high-tensile strength steel sheet having reduced variation in sheet thickness after cold rolling, and to provide its production method. SOLUTION: The range from the tail end to at least to≤200 m in a hot rolled coil has a structure essentially consisting of bainite, the fraction of pearlite in the structure is≤15%, and the difference of the variation in the longitudinal direction of the pearlite fraction is≤10%. In its production method, cooling is performed under the condition where L calculated using formula (1) satisfies≤20μm; wherein, t is a time (s) on and after the outlet side in finish rolling; t<SB>600</SB>is a time (s) till 600°C with a finish rolling completion time as zero; and T is a steel strip temperature (°C) on and after the finish rolling. COPYRIGHT: (C)2007,JPO&INPIT
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