Galling Failure Analysis in Sheet Metal Forming Process

Galling is a known failure mechanism in sheet metal forming operations,and it can lead to fracture of the products and jamming of the tool. The temperature field and normal contact pressure distributions of the tool and the blank were studied with a finite element analysis model under the action of different blank holder force and frictional coefficient. A series of forming tests of the high strength steel were conducted to validate the finite element model. The characteristics of galling failure,the damaged surface of the product and the adhesive wear of the tool,were analyzed during the forming process. The results demonstrate that die corner is the region where temperature and normal contact pressure are high and galling failure initiates. The blank surface passing through the die corner usually has the galling problem. The blank holder force and the tool surface topography have strong effects on the galling behavior in sheet metal forming processes. The methodology using finite element analysis to predict galling failure behavior can be used to perform parametric and material studies on the galling failure.