One-step pretreatment method of metallic substrates for metal cold forming

A method for pretreatment of a metallic substrate for a subsequent metal cold forming process, said method comprising at least steps (1) and (2) and optionally step (3),

• (1) providing at least one substrate having at least one surface at least partially made of at least one metal,
• (2) contacting the at least one surface of the substrate provided in step (1) with an aqueous lubricant composition (B) having a pH value in the range of from 0.1 to below 2.0,
• wherein the aqueous lubricant composition (B) comprises, in addition to water, which is present in composition (B) in an amount of at least 40 wt.-%, based on the total weight of composition (B):
• (b1) at least one film-forming polymer, which is a homopolymer and/or copolymer being prepared by polymerization of at least vinyl pyrrolidone as at least one monomer, wherein said homopolymer and/or copolymer has a weight average molecular weight in the range of from 1,000 to 100,000 g/mol,
• (b2) at least one wax, which is different from constituent (b1),
• (b3) at least one corrosion inhibitor, which is different from both constituents (b1) and (b2), and
• (b4) oxalate anions and not any phosphate anions
• and
• (3) optionally drying the coating film obtained after having performed step (2).