Abstract: In the process for the production of conversion layers continuously on a continuously moving band or sheet-like metal surfaces of aluminum, zinc or iron, by the application of a solution creating a layer on said metal surfaces selected from the group consisting of a chromating solution, an acid solution free of chromic acid and containing fluorides and compounds of titanium, zirconium or manganese, an acid solution free of chromic acid containing fluorides, and an acid solution free of chromic acid containing compounds of titanium, zirconium or manganese, by the stationary spray method, onto the cleaned and rinsed metal surface, and subjecting said metal surfaces to customary aftertreatments, the improvement consisting in that said solution creating a layer on said metal surfaces is sprayed through at least one two-component jet spray nozzle with the aid of an inert compressed gas where said solution and said compressed gas are fed separately each to an opening in said two-component jet spray nozzle.