Improvement of Tribology Properties St37 Steel by Formation of Composite Layer Containing Alumina Particles by GTAW Welding Method

The St37 steel has low hardness and low wear resistance. The purpose of this study is improvement of tribology properties this steel by formation of a composite layer containing alumina particles by GTAW welding method. To do this، the steel surface with 10% volume of alumina particles at three different currents of 90، 110 and 130 Amper with this method was covered. Reciprocating wear test، for wear resistance of the samples was carried out and their wear surfaces were examined by scanning electron microscopy. The results show that the coating of this process is having freeze-dendritic structure containing the alumina particles. The presence of these particles with reducing heat input cause increasing hardness and improvement wear behavior of the coatings. The range of increasing hardness the coatings made between 225 to 332 Vickers was measured and the amount hardness of the uncoated sample is about 180 Vickers. The results of the wear behavior of the coatings represent a significant improvement in their wear behavior in presence of the alumina reinforce with reducing heat input. The main mechanism of wear in the uncoated sample and the coated samples is adhesive wear.