Volume 39, Issue 3 (May 2011)
Elements to Improve Galling Resistance Test Results Using the ASTM G98 Method
The ASTM G98 Standard Test Method for Galling Resistance of Materials describes a relatively easy and quick method to screen materials for galling resistance. It has been used for several decades by material producers to report the galling resistance of their various grades of material. Design engineers subsequently use the data to make informed decisions regarding material selection. One of the most attractive features of the method is the small number of replicates that need to be run to estimate galling resistance. In the minimal case, only two replicates need to be tested. In recent years, however, research has been conducted that exposed several issues with the ASTM G98 method that can lead to reduced accuracy in results. These issues have included stress concentrations in the contact region, inconsistent oxidation layer formation on specimens, and small sampling sets leading to statistically insignificant results, among other issues. In this paper, several problematic issues are described and discussed. Suggestions are given to improve the repeatability of test results while still conforming to the standardized test method.