Wear coefficient of tungsten carbide against hot-work tool steel disc with two different pin settings

Pin-on-disc wear tests of tungsten carbide inserts against hot-work tool steel disc were carried out, with loads of 40 and 50 kgf, speeds of 100 and 130 m/min; and temperatures of 25, 200, 400 and 600 degreesC. Two types of insert (pin) settings were used. With the first type, the insert was set in full contact with the disc throughout the whole testing cycle. In the second type, the insert was set with an initial angle with the disc at the beginning of the wear test, but would have a full contact at the end of the testing cycle. It was found that, with the same testing parameters, the wear coefficient values of the inserts with an initial angular setting were significantly lower than those obtained with inserts that maintained a full contact setting with the counter disc throughout the testing cycle. The ratio of these two wear coefficient values, the wear coefficient ratio, was also found to be an important parameter. Lower wear coefficient ratios were generally obtained in the early stage of transient wear as well as with higher testing temperatures. This work has, therefore, provided a significant new insight into the discrepancy of the wear coefficient values obtained previously by the turning method and those by the standard pin-on-disc testing method. (C) 2004 Elsevier B.V. All rights reserved.