Repeated impact resistance of Stellite 6 hardfacing layer produced by gas metal arc welding

Cobalt-chromium-based alloys, such as Stellite 6, exhibit exceptional wear resistance, chemical stability, and thermal stability, making them suitable for demanding industrial applications. However, their use as bulk materials is limited by high hardness and poor machinability. Hardfacing represents an effective approach for applying Stellite 6 as a functional surface layer, combining enhanced surface performance with favourable bulk properties. Arc-based hardfacing technologies enable the effective preparation of such layers with high productivity and geometric flexibility. Whilst prior research has concentrated on the thermal, chemical and certain mechanical properties of Stellite 6 hardfacing layers, their response to repetitive impact loading has been the subject of only limited attention. In our work were the hardness and repeated impact resistance of the samples assessed in relation to their local microstructure and in-plane anisotropy. Impact tests were carried out at positions corresponding to individual beads and bead overlap regions. Despite the fact that bead overlap exhibited slightly reduced hardness and modified crater deformation behaviour, no measurable difference in impact lifetime was observed. The impact response was discussed in terms of deformation mechanisms, including the role of the surface tribolayer. The layer exhibited isotropic behaviour across the surface plane. Ultimately, the Stellite 6 hardfacing layer significantly increased impact lifetime compared to the steel substrate without hardfacing.