| 摘要 |
PURPOSE:To obtain a steel plate with superior strength and toughness by rolling a steel having a conventional composition under prescribed conditions in the 1st pass, and carrying out the 2nd-pass rolling after the passage of a prescribed time to make the ferrite grain structure fine. CONSTITUTION:A steel having the composition of a conventional carbon steel is rolled at 750-950 deg.C and >=30% draft in the 1st pass, and the 2nd-pass rolling is carried out after the passage of 2-6sec. The steel may be further rolled at <=4sec intervals. By this method the grain size is made small without adding elements, and a hot rolled steel plate with superior ductility and toughness is obtd. |
