METHOD FOR MANUFACTURING SUPER HIGH STRENGTH ALLOYED GALVANIZED STEEL SHEET HAVING EXCELLENT ALLOYING CHARACTERISTICS

摘要

The present invention provides a method for manufacturing a super high strength alloyed galvanized steel sheet, including the steps of: annealing a steel sheet including one or two or more species among C: 0.1~0.3%, Si: 0.1~1.5%, Mn: 2.0~3.0%, P: 0.001~0.10%, S: 0.010% less, Al: 0.01~0.1%, Cr: 0.3~1.0%, B: 0.0010-0.0030%, Ti: 0.01~0.1%, N: 0.001~0.01%, and Nb: 0.02~0.05%, Mo: 0.01~0.2%, V: 0.01~0.2% and W: 0.01~0.2% by weight%, and including residual Fe and inevitable impurity; cooling the annealed steel sheet; galvanizing the cooled steel sheet by dipping the cooled steel sheet into a galvanizing bath, where a temperature (T) of a cooling zone satisfies a value of 30 ~ 70 of a below relation equation 1; and performing alloying treatment of the galvanized steel sheet through induction heating. In the alloying treatment step, a threading speed (V) has a value equal to or above 70 of a below relation equation 2. Relation equation 1 : -334.1+762C +76.8Mn+43.5Cr-0.224T+0.00069T2, Relation equation 2: {17160-(156*value of relation equation 1)}/threading speed(V)(mpm).;COPYRIGHT KIPO 2014