Multi-layer composite cold-rolled steel plate and manufacturing method therefor

Abstract

Disclosed is a multi-layer composite cold-rolled steel plate, provided with an upper surface layer, a lower surface layer and at least one interlayer between the upper surface layer and the lower surface layer in the thickness direction of the steel plate, wherein the phase proportion of austenite in the microstructure of the upper surface layer and the lower surface layer is ≥95 %, and the at least one interlayer comprises at least one first interlayer, with the phase proportion of martensite in the microstructure of the first interlayer being ≥85 %. In addition, further disclosed is a method for manufacturing the multi-layer composite cold-rolled steel plate above, the method comprising the steps of: (1) preparing billets for various layers and assembling the billets; (2) rolling; (3) acid pickling and cold-rolling; (4) annealing; and (5) acid pickling and then heating.

Dependencies are inferred from the claim text.