HIGH STRENGTH THIN SPECIFICATION HIGH CORROSION RESISTANCE STEEL AND MANUFACTURING METHOD THEREFOR

摘要

Disclosed are a high strength thin specification high corrosion resistance steel and a manufacturing method therefor. The chemical ingredients of the steel in percentages by weight are as follows: 0.02-0.06% of C, 0.1-0.5% of Si, 0.4-1.7% of Mn, ≤0.02% of P, 4.0-6.0% of Cr, 1.0-3.0% of Ni, ≤0.007% of S, 0.004-0.010% of N, <0.001% of Als, 0.001-0.006% of B, 0.007-0.020% of total oxygen [O]_T, and the balance is Fe and inevitable impurities, and same simultaneously satisfy: comprising one or both elements of 0.01-0.08% of Nb or 0.01-0.08% of V; and Mn/S ≥ 250. In the invention, microalloy elements such as Nb/V and a B element are selectively added to steel, the basicity of slag, the type and melting point of the inclusion in steel, the content of free oxygen in molten steel and the content of acid-soluble aluminum Als during the smelting process are controlled, and a strip is then cast by means of twin-roll thin strip continuous casting, and enters an online rolling mill for hot rolling in closed conditions, and after rolling, the strip steel is cooled by air atomization cooling.