Investigating the effect of optimal addition of Inconel 718 machining swarfs on the wear behavior of gray cast iron

In this research, the optimal influence of adding Inconel 718 machining swarf on the wear characteristics of gray cast iron composites, utilizing varying proportions (1.5, 3, and 5 wt%) through the investment casting process, was investigated. The addition of a 1.5 wt% of swarf resulted in the refinement of A-type graphite into finer forms, along with a small quantity of compacted graphite. Moreover, increasing the swarf amount to 3 and 5 wt% revealed the presence of Widmannstätten's graphite in the resulting composites. By incorporating 1.5 wt% of swarf, the pearlite matrix within the cast iron was refined to a finer pearlite. Nonetheless, in instances where swarf was present in higher concentrations near the transition interface, the formation of phosphide eutectic or steadite phases, along with carbides and, in some cases, martensite, was detected. The incorporation of 1.5 wt% of swarf resulted in an increase in the hardness of the sample from 180 HB to 202 HB. Furthermore, the composite samples containing 3 wt% and 5 wt% of swarf achieved hardness values of 211 HB and 250 HB, respectively. The presence of undissolved carbides alongside hard phases like martensite caused an increase in microhardness at the interface, which peaked at 740 HB. Despite the high hardness, the wear rate of the samples with 3 wt% and 5 wt% of swarf increased by 32% and 78% respectively compared to the cast iron sample, but in the sample with 1.5 wt% of swarf, a 34% decrease in the wear rate was observed. The optimal amount of added Machining swarfs was 1.5 wt% to improve wear properties.