| 摘要 |
<p>PURPOSE:To economically manufacture a fine-grained high toughness thick steel plate for structural use with good productivity. CONSTITUTION:The slab of steel for structural use which is heated to >=Ac3 point after solidifying is applied to rolling reduction, if necessary, thereby the surface temp. is dropped to the temp. range of <=Ar3 point at >=2 deg.C/sec cooling rate. After that, it is recuperated, and the central part of the plate thickness is rolled at >=30% draft in the temp. range of (the recrystallization finishing temp. to the recrytallization finishing temp.) +150 deg.C. Once, the rolling is stopped, and cooling is executed to the <=Ar3 point surface temp. at >=2 deg.C/sec cooling rate. After recuperation, the central part of the plate thickness is rolled at >=50% draft in the unrecrystallized region, and the rolling finishing temp. is regulated to >=the Ar3 point. In this way, the objective steel plate excellent in the toughness of the base metal can stably and economically be manufactured.</p> |
