| 摘要 |
PURPOSE:To obtain a high tension steel plate with superior toughness by combining rolling in a temp. zone under the recrystallization temp. with rapid cooling after the rolling to form a hyperfine ferrite crystal structure. CONSTITUTION:A steel material is heated to Ac3-1,250 deg.C, and it is rolled by one-pass rolling in a temp. zone under the recrystallization temp. at a total draft at which the thickness is reduced to >=50% of the final thickness. The temp. zone ranges from the ferritic transformation temp. to the ferritic transformation temp. +50 deg.C. Multi-pass continuous rolling may be carried out at <=3sec intervals. Cooling is started within 3sec after finishing the rolling, and the resulting plate is cooled to a temp. below the temp. at which the ferritic transformation is finished at >=10 deg.C/sec cooling rate. |
