Continuous improvement of quality and cost saving in manufacturing of machine parts result in the search for an alternative materials for high temperature applications. In the present study a comparaison of cobalt-matrix material and iron based material for PTA hardfacing is presented. These materials are used for plasma hardfacing of sealing surfaces of industrial valves operating at elevated temperatures. The feed stock powders were compared in terms of particle geometry and quality. The deposits were made by continuous current and by pulse current of 3 and 100 Hz. The samples were subjected to thermal stress at 600 ˚C for 3 hours. The geometry and the structure of deposits were compared. Microhardness were meassured on cross section of the deposits. It was found that the iron based materials becomes harder after heat treatment. Even that they present lower hardnes than cobalt based ones.Keywords: pulsed-PTA, hardfacing, cobalt-based alloys, iron-based alloys, microhardness
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