5.1 This test method is designed to simulate the geometry and motions that are experienced in many types of rubbing components whose normal operation results in periodic reversals in the direction of relative sliding. The wear resulting from this mode of movement may differ from that experienced by the same materials sliding continuously in only one direction (unidirectional sliding, for example, using Test Method G99) even for comparable durations of contact. This is particularly true for liquid-lubricated tests where the reversal of motion means that the entrainment velocity transitions through zero but also in unlubricated tests in which stress reversal occurs. The normal load(s) and sliding speed(s) to be used during testing are to be determined by the severity of the proposed application or purpose of the testing. Either of two sets of testing conditions (designated Procedures A and B) may be used.

1.1 This test method covers laboratory procedures for determining the sliding wear of ceramics, metals, and other candidate wear-resistant materials using a linear, reciprocating ball-on-flat plane geometry. The direction of the relative motion between sliding surfaces reverses in a periodic fashion such that the sliding occurs back and forth and in a straight line. The principal quantities of interest are the wear volumes of the contacting ball and flat specimen materials; however, the coefficient of kinetic friction may also be measured using the method described. This test method encompasses both unlubricated and lubricated testing procedures. The scope of this test method does not include testing in corrosive or chemically aggressive environments or extremes of temperature and humidity.

1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.