Wear properties of the materials are represented by size/ depth of the wear scars. According to Fig. 19, Alloy 1 gives the deepest scar, followed by Alloy 2 and finally Alloy 3. The average depth of the three alloys is 0.0146 in, 0.0142 in., and 0.01, respectively. The amount of material removed from each alloy is shown in Fig. 20. The material removed from Alloy 3 represents only 50% of that removed from the Al- loys 1 and 2. This means that Alloys 1 and 2 are softer than Alloy 3 and may provide increased conformability and em- bedability. This could result in a better bearing performance
since those two important characteristics allow the bearing to adapt to shaft misalignment and to operate in a harsher en- vironment by absorbing dirt, grit and other foreign particles that may otherwise damage the shaft. It may be noted that the rub tests performed in this study were aimed at determin- ing the friction properties of the various materials and do not represent in any case an operational wear that bearings see in service. The shaft and bearing should never be in direct contact since there is always a lubricant film that separates both surfaces while in relative motion.
(a) BSE micrograph, 400X
(b) Particle 1
(c) Particle 2 Figure 14. SEM micrograph and EDS of phases present in Alloy 1 (N6178-4S).
(d) Particle 3
28
International Journal of Metalcasting/Winter 10
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