Experimental study on surface topography and fracture strength of worn saw wire in multi-wire sawing

Abstract

In multi-wire sawing, reducing the wire wear loss and increasing wire consumption are the common means to avoid the risk of saw wire breakage because the worn saw wire experiences a complex process with strength degradation and surface damage. So, it is urgent and necessary to give a reliable wire wear loss in theory. This paper focused on the surface topography and fracture strength of worn wire with different wire wear loss. Furthermore, the saw wire maximum safety wear loss model was presented based on the experimental results. By observing the surface topography of the worn saw wire, the dented traces were distributed on the whole surface and a few grooves with large depth were shown in the local zone. The cross-sections of the worn saw wires with different wear loss were circular. In addition, its fracture strength of the wore saw wires was not reduced with the increasing of the saw wire wear loss. On the contrary, the fracture strength of the wire with large wear loss was improved by hardening in comparison with fresh saw wire. This phenomenon suggested that surface damages did not affect the fracture strength of saw wire under the experimental condition. Furthermore, fracture photograph of the fracture test samples was divided into the crack propagation zone and final fracture zone. By analyzing these fracture topography, almost all the crack propagation zones were circular and its diameter was about 48.27 μm. It is not correlated with the amount of wear loss. However, the shape became non-circular in some samples with large depth damage on the surface. By summarizing these results, the model and calculation method of the maximum safety wear loss of saw wire were established, which could provide the theoretical basis for the determining the maximum safety wear loss.