Friction Measurement by Upsetting with Asymmetric Interface Friction

The upsetting of flat plates offers several ways to analyse the influences of surface microstructure, lubrication and material on friction. If the friction conditions at the two interface areas are different, the inflection of the billet gives a measure for the friction difference. The advantage of this test is that friction measurements with high speeds and full deformation are possible, e.g. drop forging. In traditional friction tests the forming speed is too low or the specimen is deformed only at the surface. In several metal forming processes, e.g. rolling, friction conditions cannot be described precisely because of the unknown behaviour of the lubricant at high pressure and at a high deformation speed. In addition, asymmetric friction conditions can be transferred to asymmetric conditions in rolling. Friction measurement with upsetting of flat specimens is cost effective and does not require large-scale equipment.