Wear behaviour of hardfaced Fe-Cr-C alloy and austenitic steel under 2-body and 3-body conditions at elevated temperature

Abstract

Fe-based hardfacing alloys are widely used to protect machinery equipment exposed to different loading situations where abrasives play a dominant role in restricting lifetime of tools. Wear at elevated temperatures is superposed by the effect of oxidation of the wearing surface. In view of the above, two hardfacing alloys based on Fe-Cr-C incorporating Nb, Mo and B to ensure improved performances at elevated temperature were deposited onto mild steel under optimised gas metal arc welding (GMAW) condition. 2-body erosive wear behaviour was evaluated from room temperature up to 650 °C under 30° and 90° impact angle. For 3-body impact/abrasion conditions tests were done with a specially designed cyclic impact abrasion tester (CIAT) at room temperature and 600 °C. The wear behaviour of the hardfacings was compared with austenitic stainless steel. Results indicate that 2-body erosive wear rate of the hardfacing increases with test temperature and with increase in impact angle, whereas wear behaviour of the austenitic stainless steel is non-sensitive to the testing temperature at normal impact. In 3-body impact abrasion testing similar behaviour can be seen; cyclic tests in CIAT at enhanced temperatures result in breaking of coarse carbides, whereas wear mechanisms of the austenitic steel result in massive abrasion and formation of a mechanically mixed layer (MML).