P 508 - Investigation of the bondability of Drylube-coated steel sheets

As some of these coatings are solid polymer films, there were concerns as to whether they could be absorbed by the usual, heat-curing bodyshell adhesives. This was checked on the basis of the similar process sequence used by all vehicle manufacturers in the bodyshell (application of the adhesive to the temporary coating, joining of the components and fixing, removal of the temporary coating in the area of the paintwork immediately before the cathodic dip coating, complete curing of the adhesive only in the cathodic dip coating oven). The tests showed that the bondability and compatibility of the Drylube dry lubricants analysed can generally be described as good. Individual incompatibilities were identified and explained using damage models. Initial optimisation approaches were examined and show possibilities for avoiding weak points. The results of this research report thus make a significant contribution to the optimisation of production processes in body-in-white construction, particularly with regard to bonded lightweight construction methods with Drylube-coated thin sheets. The objectives of the joint research were developed in a "Bonding of Steel" working group under the direction of the Forschungsvereinigung Stahlanwendung e.V., Düsseldorf. This working group includes representatives of the steel processing industry (motor vehicles, commercial vehicles, white goods) as well as representatives of the steel industry.