Effect of boronizing heat treatment on the abrasive wear in the steel castings

Boronizing is a termochemical process which boron atoms are diffused into substrate metal piece. Boronizing process result in higher hardness than other thermochemical process like nitriding, carburizing, During the boronizing process, the thickness and the properties of boride layer are depends on boronizing process parameters like boronizing temperature and time and boronizing media, workpiece chemical composition. In this study boronizing processes were carried out by using pack boriding method in the temperature range 850 °C, 900 °C and 950 °C at the holding time of 2, 4 and 6 hours. Before boronizing process, cast GS 52, GS 60, AISI 8620 and GX120Mn13 steel specimen were polished using 1200 Mesh emery paper to obtain a good surface finish. After boronizing heat treatment, microhardness measurement, X-ray diffraction analysis, microstructural observations of borided specimen was carried out. Abrasive wear tests were carried out under load of 30 N, 1200 Mesh abrasive paper at sliding speed of 0,2 m/s. Two boride layers based on the FeB and Fe2B compounds are formed at the interface of carbon steel. The thickness of boride layers was measured using optical microscope Soif XJP 6A equipped with a M-Shot MD-50 digital camera and Digital Imaging Measuring System software. GS 52 cast steel has the thickest boride layer while GX120Mn13 steel has the lowest thickness ofr boride layer. On the other experimental result show that borided Hadfield steel exhibited two times higher abrasive wear resistance than borided GS 52 cast. Effects of boronizing temperature and time, applied load, sliding distance on the abrasive wear have been investigated by using artificial neural networks. The experimental results were trained in an ANNs program and the ANNs results were compared with experimental values. It is observed that the experimental results coincided with ANNs results.Science Code915.1.093Key Words: Boronizing, abrasive wear, steel castingPage Number: 108Adviser : Prof. Dr. Ferhat GÜL