METHOD FOR MANUFACTURING THIN STRIP CONTINUOUSLY CAST 700MPA GRADE HIGH STRENGTH WEATHER-RESISTANT STEEL

摘要

A kind of thin strap continuous casting 700MPa grade high-strength weathering steel manufacturing methods comprising following steps: the 1) Cast Strip that cast thickness is 1-5mm in double-roller continuous casting machine, chemical component weight percentage are as follows: C 0.03-0.1%, Si≤0.4%, Mn 0.75-2.0%, P 0.07-0.22%, S≤0.01%, N≤0.012%, Cu 0.25-0.8%, additionally it contained more than one in Nb, V, Ti, Mo, Nb 0.01-0.1%, V 0.01-0.1%, Ti 0.01-0.1%, Mo 0.1-0.5%, remaining is Fe and inevitable impurity; 2) Cast Strip is cooled down, cooling rate is greater than 20 DEG C/s; 3) hot rolling, 1050-1250 DEG C of hot-rolled temperature, reduction ratio 20-50%, rate of deformation ＞ 20s-1 are carried out to Cast Strip; Austenite occurs after hot rolling to recrystallize online, hot-rolled strip is with a thickness of 0.5-3.0mm; 4) cooling, cooling rate is 10-80 DEG C/s; 5) it batches, 500-650 DEG C of coiling temperature. The steel band microscopic structure of acquisition is mainly made of the bainite and acicular ferrite being evenly distributed.