Method for directly producing pickling-free hot-plated sheet strip product from molten steel

摘要

Method for directly producing a pickling-free hot-plated sheet strip product from molten steel comprising: obtaining a refined molten steel; thin strip continuous casting: a mixed gas of an inert gas and a reducing gas is used for protection in the billet casting process; hot rolling: the cast strip is levelled at a high temperature so as to improve the sheet shape and rolled to a suitable thickness so as to change the product specification, or provide a mechanical disruption action on the iron oxide skin on the surface of the cast strip; reduction annealing: a sectional reduction method is used to perform sectional reductions with the temperature held within two ranges, i.e., 450-600° C. and 700-1000° C., wherein the reduction is performed within a range of 450-600° C. for 1-5 minutes and within a range of 700-1000° C. for 1-3 minutes to remove the iron oxide skin produced in the previous procedure, the concentration of the reducing gas being not lower than 5%; and hot galvanization: after having been cooled in a protective atmosphere, the strip billet is brought into a zinc bath and hot-plated with zinc and other alloy, and then cooled and coiled. The present invention realizes a highly continuous production of a hot-plated product from molten steel with iron and steel, and hot plating with zinc or an alloy is directly performed without removing elementary iron produced by the reduction, so that the energy consumption in the middle stage can be saved and the recovery of metal reaches close to 100%.