Effects of surface roughness of roll metal pins on their friction and wear characteristics

For the combinations of four kinds of roll metal pins finished by two methods and an Al-killed steel disk rolled, friction and wear tests were carried out under the boundary lubricated condition at a sliding speed of 1.88 m/s and under a constant load of 3.7 N and a constant sliding distance of 7000 m. A topographical analysis has also been performed on the micro-asperities of the wear surfaces to estimate the effect of surface roughness of metal pins and the behavior of the wear particles, the degree of surface damage, and the wear rate. As a result, the following conclusions were found. (1) In the pin on disk wear test, the wear properties of pins depended on the surface roughness on the pins, i.e., the wear rates of pins with Ra = 0.01-0.07 mu m were in the order of FH-15 < FH-15R < E61 < E70. Those of the pins with Ra = 0.2-0.6 mu m were in the order of E70 < FH-15 < FH-15R < E61. (2) The lowest wear rates and the smaller change in the surface roughness before and after test for E70 pins resulted from the protecting effect of the transferred particles to the pins. (3) The mean friction coefficient mu increased with increasing wear rates of E70 and E61 pins with Ra = 0.2-0.6 mu m in the range of mu = 0.045-0.087 and those indicated the reverse trend for the other pins. (C) 2000 Elsevier Science S.A. All rights reserved.