The invention belongs to the technical field of heat treatment, and particularly relates to a cover annealing method for high-Cr-Si alloyed hot-formed steel. Aiming at the problems of low yield, large performance fluctuation and the like caused by poor
structure property uniformity after coiling of high-
hardenability high-Cr-Si alloyed hot-formed steel, limited martensitic structure bending properties after hot forming, and unstable processes of acid
pickling welding, uncoiling blanking and hot
forming processes, the invention provides the cover annealing method for improving uniformity and bending properties of high-Cr-Si alloyed high-
hardenability hot-rolled hot-formed steel. According to the invention, after cover annealing, structure uniformity of a hot-formed steel coil is greatly improved,
internal stress is reduced, a performance difference between the head and
tail of the steel coil and the coil center is reduced, uncoiling buckling is improved, and the material loss of the edge and the head and
tail is reduced. In addition, in a cover annealing process, a decarburized layer with certain thickness can be generated on a surface of the steel coil containing the components provided by the invention under the reduction action of high-temperature
hydrogen, so that bending properties of hot-formed steel manufactured through subsequent hot forming
processing are improved.