| 摘要 |
PURPOSE:To obtain a hot rolled steel plate having superior toughness at low temp. and superior resistance to corrosion and hydrogen induced cracking by placing proper number of cooling and heating zones between a final mill and a coiler and carrying out controlled cooling and reheating according to the purpose for which a hot rolled steel plate is used. CONSTITUTION:One or more cooling zones 3, 5 and one or more heating zones 4, 6 are placed between the final hot rolling mill 1 and the coiler 5. Conditions during cooling in the cooling zones 3, 5 are controlled according to the purpose for which a hot rolled steel plate is used, and the reheating to a proper temp. is carried out in the heating zones 4, 6. Bu such a method, austenite grains are made fine, cementite and deposits are finely dispersed and these 2nd phases are uniformly dispersed in a uniform size. |
