Development of tribological and surface characterization methods for evaluation of galling of aluminum alloy sheets

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Adhesion of aluminum to tool and die surfaces (galling) during shearing operations reduces tool life and deteriorates surface quality of the sheets. Novelis Inc., a primary supplier of sheet aluminum products to the North American automotive manufactures recognizes that in order to increase product quality and production efficiency of sheared aluminum alloy sheets it is necessary to advance new mitigating strategies for preventing aluminum galling. At present, no standard method exists to measure galling in a consistent and reproducible way. This proposal is the initial step of a new collaborative program being set up between Novelis and the applicant at the University of Windsor to investigate the fundamental aspects of aluminum galling. We propose to develop methods for determination of the amount of aluminum transfer on punch dies as a function of die pressure in both dry and lubricated conditions. These will consist of three dimensional non-contact interferometry measurements along with optical microscopy with large depth of field focus. The compositional analyses of galled parts will be conducted by micro-Raman spectroscopy. The results are expected to contribute to the development of a consistent and reproducible method for the determination of galling on surfaces lubricated by industrial forming lubricants. It will also establish whether the production issues related to galling could be simulated at the laboratory scale using tribological tests. The results will be transferred to Novelis.