Adhesion and wear properties of boro-tempered ductile iron

In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 °C for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 °C for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe2B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al2O3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

► In this study, the wear and adhesion properties of BDI were investigated.
► Boro-tempering process under several heat treatment conditions was examined.
► Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure.
► It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons.