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Sheet metal forming is a widely used forming process. This process is applied to hot sheet material to improve product properties, like weight and strength. However, hot sheet metal forming also comes with some disadvantages in the form of wear. Due to the high temperatures during sheet deformation no lubrication can be applied, which allows for wear to occur more severely. Here, galling is the wear mechanism of interest, which is a form of adhesive wear. Material transfers from the sheet to the tool during relative contact displacement, which is called galling. This is a problem when the material build up on the tool becomes too large that it scratches the product. The tools have to be cleaned or even replaced, which is disadvantage to the flow and cost of the production.

A model is implemented to predict galling behavior and critical locations on the tools. This model is an extension of the existing friction model within the TriboForm software. The galling model evaluates every contact spot between the tool and sheet (asperity) to check if it is suitable for galling. Two different galling initiation models for the asperities have been proposed, one based on the shape of an asperity (wedge formation initiation model - WFI) and one based on the strength of the asperity with respect to the sheet coating (coating fracture initiation model - CFI). If an asperity is initiated it will grow during the relative contact during sliding.

This galling model is calibrated using experimental data from hot strip draw tests performed at Tata Steel. This data is valid for a calibration of adhered volume over temperature. Both the galling initiation models are calibrated using these experimental values.

Using AutoForm and TriboForm the galling behavior on the tooling for three different part are visualized: 1) the experimental B-pillar from Tata Steel, 2) the industrial A-pillar from Volvo Cars and 3) the industrial Side Member from Volvo Cars. The predicted galling depends on the temperature, pressure and strain of the sheet during deformation and on the relative sliding distance in contact between the tool and the sheet. The CFI model is more favorable when evaluating the experimental data from the B-pillar and when comparing the two industrial parts to each other.