EXTRA LOW CARBON HOT ROLLED STEEL SHEET MANUFACTURING METHOD WITH LOW MECHANICAL PROPERTY DEVIATION IN THE THICKNESS DIRECTION

摘要

PURPOSE: A method of manufacturing an extra-low carbon hot-rolled steel plate to decrease material difference in a depth direction is provided to remove solid element from steel by adding Ti and Nb and improve formability. CONSTITUTION: A method of manufacturing an extra-low carbon hot-rolled steel plate to decrease material difference in a depth direction comprises next steps. An extra-low carbon steel slab board is re-heated(S-10). The re-heated slab board is roughly hot-rolled(S-20). The roughly hot-rolled board is finishing-rolled using a multi-layered roll stand(S-30). The input temperature of the final roll stand is within 990~1010°C. The finishing rolling temperature is within 850~950°C. At the finishing rolling step, the cooling speed of the final roll stand is within 20~60°C/stand.