A method for coating an uncoated or precoated metallic or plastics substrate by (a) applying an aqueous coating composition (W) whose constituents are free or substantially free from blocked isocyanate groups, which comprises an aqueous dispersion of an epoxide-amine adduct, and which comprises either no crosslinking agent or one or more nonblocked polyisocyanate crosslinking agents, to the substrate, (b) optionally applying one or more further coating compositions, and (c) curing the coating composition (W) and, where appropriate, the further coating composition(s) at temperatures of below 90° C.