| 摘要 |
PURPOSE:To obtain a steel material having little ultrasonic anisotropy and toughness above the ordinary by specifying starting temp. of finish-rolling and finish temp. of rolling in un-recrystallized range and rolling at the specific draft. CONSTITUTION:At the time of executing control rolling to hot-rolled steel material, the starting temp. of the finish-rolling in the un-recrystallized range is specified to >=40 deg.C and <=100 deg.C higher the Ar3 transformation point and also the finish temp. of the rolling is specified to >=40 deg.C higher the Ar3 transformation point and the rolling is executed at >=30% draft. In the case of 60 deg. normal refractive angle, this steel material has the little ultrasonic anisotropy and possesses high strength and high toughness at the same time, and the steel material having high safety in the industrial field can be supplied. |
