METHOD FOR PRODUCING HIGH TENSILE SHIPBUILDING STEEL HAVING EXCELLENT PRODUCTIVITY

摘要

PURPOSE: A method is provided to produce high tensile shipbuilding steel having 50kgf/mm¬2 of tension intensity with high productivity. CONSTITUTION: A crystal grain is refined by using a static re-crystallization effect of austenite occurred in a high temperature re-crystallization area of a rolling process. After the growth of the re-crystallized grain occurred between rolling passes is rolled by the growth suppression effect of TiN extraction material, the refinement of austenite particles is promoted. The radiative heat amount and temperature descend amount are calculated based on the rolling finish temperature and a material transmission time, and the target temperature of cooling start is set up. Cooling is performed by obtaining the steel sheet transmission speed so that the high tensile shipbuilding steel is produced with high productivity by raising the cooling finish temperature.