| 摘要 |
<p>PURPOSE:To reduce residual stress and to prevent breaking by slowly cooling a roll after hardening so that the internal temp. distribution of the roll is made nearly uniform. CONSTITUTION:When a roll is hardened by heating to a prescribed hardening temp. during heat treatment, the roll is slowly cooled after the hardening so that the internal temp. distribution of the roll is made nearly uniform. At this time, the cooling rate Sc( deg.C/min) represented by the equation is regulated to <=0.9. In the equation, TSR is the maximum temp. ( deg.C) of the roll at the beginning of straion relief annealing in the next stage, T0 is a standard temp. ( deg.C) in case where residual stress in the roll is assumed to be zero, tSR is the time (min) from the beginning of hardening to the beginning of strain relief annealing, and t0 is the time (min) from the beginning of hardening to the time when the maximum temp. of the roll reaches the standard temp. T0 ( deg.C).</p> |
