Thermodynamic simulation as an assistant tool in the development of iron based hardfacing materials

Abstract

A thermodynamic model was used to investigate the solidification of a hardfacing material in Fe-Cr-C-Nb system designated CNO, and developed for cladding components subjected to severe abrasive wear by welding. Microstructural characterization of the alloy showed that the theoretical simulations carried out to predict the amount and volume fraction of the phases using the module Scheil of MT-DATA Software gave very realistic results in the case of the rapid solidification of the hardfacing alloy CNO. The results obtained in this study indicate that the utilization of this tool may provide a good understanding of alloys solidification. As a consequence, it is possible to enable the refinement of alloy composition during the early stages of hardfacing materials development, leading to a decreasing of overall cost and time of manufacturing of hardfacing electrodes.

The effect of microstructure on abrasive wear of a Fe–Cr–C–Nb hardfacing alloy deposited by the open arc welding process

“…From the figure, it can be seen the presence of a high volume of randomly dispersed primary NbC (bright phase), which was confirmed by XRD and EDS results showed in Fig. 3 and Table 3 [10]. With relation to the primary M 7 C 3 carbides, it can be noted in this alloy that these particles appear as smaller needles than those observed in the HCO alloy.…”

“…3) and EDS microanalysis results in two different regions of the matrix (Table 3) showed that this region was widely enriched of Cr and Fe. These results and the morphology of the phases strongly indicate that matrix region is eutectic mixture γ (austenite)/M 7 C 3 [10] and [12].…”

“…A steel shaped sheath was filled with mixtures of commercial powders and compressed down to a diameter of 2.8 mm by rolling [10].…”

“…Openarc welding is a cost-effective automatic welding technique particularly suited to hardfacing applications. This technique has the merit of dispensing flux and shield gas as well as being able to use a large electric current for enabling faster welding rates than other conventional welding process [10]. The weld deposit consisted of 6 layers overlapped (approximately 14 mm height) and was processed by depositing several beads.…”

“…As carbides are prone to fall off from a matrix during the wear process, the resulting volume loss of material from the surface can often be more intense resulting in severe wear [7][8][9] and [10].…”