Simplified method for pretreating metal substrates for cold forming and reactive lubricant therefor

A process for a pretreatment of a metallic substrate for cold forming, wherein the metallic substrate is successively

• 1) optionally mechanically or chemically cleaned and subsequently rinsed,
• 2) optionally pickled and subsequently rinsed,
• 3) brought into contact with a water-based, acidic, reactive lubricant comprising
• a) oxalic acid,
• b) at least one accelerator which comprises nitroguanidine and/or at least one iron(III) source, and
• c) at least one emulsified lubricating oil, and optionally at least one film former and/or at least one wax, and
• 4) optionally dried,
• wherein the at least one film former is selected from the group consisting of homopolymers and copolymers of ethylene, propylene, styrene, (meth)acrylic acid, (meth)acrylate, vinylamine, vinylformamide, vinylpyrrolidone, vinylcaprolactam, vinyl acetate, vinylimidazole and/or epoxide and salts thereof, and polyurethanes, polyamides, polyethyleneimines, polyamines and salts thereof,
• wherein the at least one wax is selected from the group consisting of nonionic waxes and cationically stabilized waxes,
• wherein the at least one emulsified lubricating oil is selected from the group consisting of synthetic oils, mineral oils, vegetable oils and animal oils, and
• wherein a pH of the reactive lubricant is less than 2.0.