A method of manufacturing a steel strip of high strength by walmwalzen

摘要

A process for manufacturing a hot rolled strip of high tensile steel, including carbon, manganese and silicon are included, by weight, between 0.04% and 0.2%, between 0.5% and 2% and between 0.01% and 0.5% respectively. The steel further contains niobium in an amount between 0.01% and 0.1% by weight, the remainder being iron and the usual impurities. Is carried out hot finish rolling of the steel between an initial temperature lower than 950 degree C. and a final temperature higher than the transformation temperature of austenite into ferrite (Ar3), with a thickness reduction rate of at least 85%. Within less than 5 s, and preferably less than 1 s, after the hot rolling, the steel is cooled continuously and monotonically with a cooling rate of 20 degree C / sec from the final temperature above to a temperature lower than 200 degree C. and the hot rolled steel strip is coiled at that temperature less than 200 degrees C.