The invention relates to a production method of 600MPa grade cold rolling dual-phase steel and belongs to the technical field of metallurgical
sheet material production. The technical scheme of the production method comprises working procedures of
smelting in a converter, LF (
ladle furnace) refining,
continuous casting, hot rolling, cold rolling and
continuous annealing. The final chemical components according to
mass percent are as follows: 0.06-0.09% of C, 0.4-0.6% of Si, 1.65-1.75% of Mn, less than or equal to 0.01% of P, less than or equal to 0.015% of S, 0.025-0.06% of Als, less than or equal to 0.004% of N, and the balance of Fe. Molten iron requirements in the procedure of
smelting in the converter are as follows: S is less than or equal to 0.040%, desulfurization target S is less than or equal to 0.010%, added steel
scrap is 4-8% of total
mass of the molten iron, and hot
metal ratio is more than or equal to 85%. In the production method, no
alloy element is added; composition of C-Si-Mn series dual-phase steel is improved; Si content is decreased;
Al content is increased; and cold rolling dual-phase steel with low
yield ratio and high elongation coefficient is produced by improving
smelting, hot rolling, cold rolling and
continuous annealing processes; the cost is low; the production procedures are continuous; and the product quality is stable. The
mechanical property of the finished product is as follows: yield strength is about 360-430MPa, tensile strength is more than or equal to 600MPa, and elongation coefficient is more than or equal to 25%.