In order to more accurately simulate wear behavior that occurs in the field (i.e., impact coupled with abrasion), an impeller-in-drum wear test has been developed. The apparatus is similar to the one first developed by Bond; however, in the apparatus used at the Albany Research Center, three paddles instead of just one are situated in the drum which can be impacted and abraded during the course of the wear test. In using three paddles, a standard can be run at the same time as the specimens of interest. Two test procedures have been developed which provide information on the relative resistance of a material to the combined action of impact and abrasion. In the first procedure, the wear samples are run for 1 h on each side of the specimen paddle. This average value of the two tests gives an upper average limit to the impact-abrasive wear of the material, but has the advantages of being easy to run and relatively quick. The second procedure attempts to determine the steady-state wear behavior by running sequential wear tests on one surface of the specimen paddle. In this procedure, anywhere from three to five l-h tests are run on one surface of the paddle. The cumulative mass or volume loss is plotted as a function of time and the slope of the linear portion of the curve provides the value for the steady-state wear rate. In addition to describing the experimental procedure, wear mechanisms will be discussed and the changes that occur in the microstructure as a result of the wear tests will also be described. The way various alloys behave in pure abrasion and in impact-abrasion will be discussed, highlighting the change in a material's wear behavior with a change in wear mode. (C) 1999 Published by Elsevier Science S.A. All rights reserved.
