Tribological testing of top hammer drill buttons

Abstract: In the present work further modifications are implemented to an existing test setup for the evaluation of the wear of cemented carbide drill buttons in rock drilling applications. The test setup has been evaluated in previous diploma works, which has shown that the test successfully mimics the wear seen in rock drilling applications. The new modifications include friction and normal force measurements together with the collection of rock debris. This has been made possible by redesigning the sample holder and by manufacturing equipment making rock debris collection possible. The new modifications to the test setup were evaluated by comparing the wear of three different cemented carbide grades tested against sandstone and granite with two different loads. The data collected from the new modifications were found to be robust with lower than expected spread of data. The coefficient of friction when testing against sandstone was higher than when testing against granite. More adhered material was observed on the wear surface when testing against granite than against sandstone. Load dependence on the wear of the cemented carbide buttons is only seen for the softer cemented carbide grades when testing against sandstone. The wear of the buttons indicates a high dependence on the hardness of the different grades as shouldbe expected. This diploma work has been performed for Sandvik Mining, Rock Tools,a world leading supplier of rock drill equipment.