The abrasion test was conducted on samples of cast iron, produced by various methods and annealed at various temperatures, with a rotor made of pearlite matrix annealed at 550°C. The following results were obtained.
1) The residual stress of the specimen produced in gravity green sand mold (specimen mark; L) was greater than that of specimen in dry sand mold (Q) by centrifugal casting. The residual stress gradually decreased with the rise of annealing temperature when it was below 450°C; however, the stress was rapidly removed at 450-550°C.
2) The relation between annealing temperature and wear loss was examined. Under the condition of the wear with mechanical rupture, the minimum wear loss was observed at 450-550°C in specimen L, or at 550-600°C in Q.
3) When residual stress increased to a certain value, rapid increase of wear loss was observed.
The critical value of the residual stress was called “Critical residual stress for wear.”
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