SIMPLIFIED METHOD FOR PRETREATING METAL SUBSTRATES FOR COLD FORMING AND REACTIVE LUBRICANT THEREFOR

The present invention relates to a simplified method for pretreating metal substrates for cold forming, in which method a metal substrate is successively 1) preferably cleaned and then rinsed, 2) preferably pickled and then rinsed, 3) brought into contact with a water-based, acidic, reactive lubricant, which contains a) oxalic acid, b) at least one accelerator, which comprises nitroguanidine and/or at least one iron(III) source, and c) at least one film former, at least one wax and/or at least one emulsified lubrication oil, 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, vinyl amine, vinyl formamide, vinyl pyrrolidone, vinyl caprolactam, vinyl acetate, vinyl imidazole and/or epoxy and salts thereof and polyurethanes, polyamides, polyethylene imines, polyamines and salts thereof, wherein the at least one wax is selected from the group consisting of non-ionic waxes and cationic stabilized waxes, and wherein the at least one emulsified lubrication oil is selected from the group consisting of synthetic oils, mineral oils, vegetable oils and animal oils, to a corresponding reactive lubricant and to a metal substrate pretreated by the method and use thereof. La presente invención se refiere a un proceso simplificado para el pretratamiento de sustratos metálicos para el conformado en frío, en donde un sustrato metálico sucesivamente es 1) preferiblemente limpiado y posteriormente enjuagado, 2) preferiblemente decapado y posteriormente enjuagado, 3) puesto en contacto con un lubricante reactivo, ácido, a base de agua que comprende a) ácido oxálico, b) al menos un acelerador que comprende nitroguanidina y/o al menos una fuente de hierro (III) y c) al menos un formador de película, al menos una cera y o al menos un aceite lubricante emulsionado y 4) opcionalmente se seca, donde al menos un formador de película se selecciona del grupo que consiste en homopolímeros y copolímeros de etileno, propileno, estireno, ácido (met)acrílico, (met)acrilato, vinilamina, vinilformamida, vinilpirrolidona, vinilcaprolactama, acetato de vinilo, vinilimidazol y/o epóxido y sales de los mismos y poliuretanos, poliamidas, polietileniminas, poliaminas y sales de los mismos, donde al menos una cera se selecciona del grupo que consiste en ceras no iónicas y ceras estabilizadas catiónicamente, y donde al menos un aceite lubricante emulsiona