Manufacturing method of 0.4-0.8 mm thick high-carbon alloy structural steel

The invention discloses a manufacturing method of a 0.4-0.8 mm thick high-carbon alloy structural steel. The structural steel comprises the following components in percentage by weight: 0.25-0.55% of C, 0.15-0.35% of Si, 0.10-2.0% of Mn, 0.10-2.0% of Cr, less than or equal to 0.030% of Alt, less than or equal to 0.020% of P, less than or equal to 0.010% of S, no more than 0.3% of other added alloy elements, and the balance of iron and inevitable impurity elements. The manufacturing method comprises finish rolling, acid pickling, first cold rolling, intermediate annealing, second cold rolling, and finished product annealing. The product of the target thickness specification, which is obtained through twice cold rolling and twice annealing for a hot-rolled product that is previously pickled with acid, has good formability and surface quality; precise parts complex in shape and high in precision can be manufactured; in addition, the technical problems of a failure in interpenetration caused by deformation due to a high thickness and a low single-pass cold-rolling reduction ratio of a cold-rooked product and poor formability of the steel strip due to no annealing after the completion of the second cold tooling in the prior art are solved.