Method for preparing shaped metal bodies for cold working

The invention relates to a method for treating shaped bodies having a steel surface having a carbon content in the range of 0 to 2.06 wt% and a chromium content in the range of 0 to < 10 wt% before cold working, wherein at least one shaped body is brought in contact with an aqueous acidic composition in order to form a conversion layer as a separating layer, wherein the aqueous acidic composition is prepared only with a formulation that consists substantially of water, 2 to 500 g/L of oxalic acid, and (a) 0.01 to 20 g/L of at least one accelerator based on guanidine and/or (b) 0.01 to 20 g/L of at least one nitrate and optionally of pigment, surfactant, and/or thickening agent, wherein the pickling removal of the aqueous acidic composition is in the range of 1 to 6 g/m2, wherein the layer weight of a dried conversion layer is in the range of 1.5 to 15 g/m2, wherein the ratio of pickling removal to layer weight PR : LW of the dried conversion layer is in the range of (0.30 to 0.75) : 1 and wherein the dried co