An Investigation on Wear Behaviour of ASTM B23 tin-Based Babbitt Alloy Developed Through Microwave-Assisted Casting

Abstract

Casting is one of the preferred additive manufacturing techniques which controls the formation of phases and their morphological size during processing of the material. The properties of material like hardness and wear resistance depends upon the microstructure, amount and size of the hard phases present in the alloy. Recently, a new technique called microwave-assisted casting has been introduced. In this casting technique, microwave energy is utilized to manufacture a casting. For this a microwave furnace is required. The process of heating, melting the charge, pouring, solidification and cooling of the casting takes place inside the microwave furnace. In the present work, microwave-assisted casting technique is used for producing castings of ASTM B-23 Tin-based Babbitt alloy. The major focus of the study was to investigate the effect of microwave casting on the wear behaviour of the Babbitt alloy. Accordingly, cast specimens were also produced by conventional casting technique. Both the cast specimens were compared for wear behaviour. The microstructure analysis of the cast specimens of Babbitt alloy was done to study the phases and their distribution. The microstructure indicated the presence of three constituent phases, the solid solution of antimony (Sb) and copper in tin (Sn) is the basic α-phase; the β-phase is cubic crystals of Sn-Sb and η-phase is in the form of needles of Cu₆Sn₅. XRD analysis was done. It was found that as compared to conventional cast specimens, the amount of β-phase of Sn-Sb was 14.4% and η-phase of Cu₆Sn₅ was 13.4% more in the microwave cast specimen. On the other hand as compared to conventional cast specimens, the amount of α-phase was 27.8 % less in the microwave cast specimen. Rockwell hardness testing of the cast samples was also carried out. It was observed that hardness of the microwave-assisted cast samples was 1.4 times higher than conventional cast samples. Wear testing of the cast pins was done using Pin-on-Disc tribometer. It was found that wear resistance of microwave assisted cast pin was 3.339 times the wear resistance of conventional cast pin.