| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a thick steel plate inexpensively even with the satisfactory productivity, which is superior not only in arresting characteristics but also in ductile-fracture properties. <P>SOLUTION: This manufacturing method comprises giving an equivalent plastic strainεonto the surface region of the steel plate so as to makeε≥0.5 in a non-recrystallizing-temperature region, then cooling the surface region to a temperature range of 450-650°C at a cooling rate of 2-15°C/s, within a period during which the amount of residual accumulated equivalent plastic strainεr in the surface region satisfiesεr≥0.5, while keeping a temperature of the inner region of the steel plate to the Ar<SB>3</SB>transformation point or higher, then restarting rolling so as to give the residual accumulated equivalent plastic strainεr in a range of 0.35≤εr<0.55 to the above inner region, finishing the rolling at the Ar<SB>3</SB>transformation point or higher, to recuperate heat in the above surface region to the Ar<SB>3</SB>transformation point or lower due to the working heat and the inner sensible heat, and then cooling it with the average cooling rate kept to 1-10°C/s. <P>COPYRIGHT: (C)2003,JPO</p> |
