The edge effect of specimens in abrasive wear testing

In abrasive wear testing, the specimen edges may exhibit increased wear rates. To determine the extent of edge wear, a series of tests was conducted with the crushing pin-on-disk device. The test pin was divided into two sections, separating the wear area into inner and outer pin areas. The tests were conducted with granite and quartz rocks of varying size. The edge effect was determined as the difference of the mass loss of a specimen comprising both the inner and outer parts and the mass loss of the inner part alone scaled to the size of the combined pin area, representing a specimen without edge wear. The tests showed increased edge effect with larger rocks, depending on the mechanical strength of the abrasive material. When using only large rocks with good mechanical strength, the edge effect could be as high as 50% of the total specimen mass loss, whereas with more fragile rocks of smaller size, the edge effect was close to 0%.