Effect of Steel and Tungsten Carbide Ball Indenters on Rockwell Hardness Tests

Rockwell hardness (HR) is a valuable and widely used indentation hardness test for evaluating mechanical properites of metallic materials. For the Rockwell scales that use a ball indenter, either a steel or tungsten carbide (WC) ball indenter is permitted to be used in the test method standards of ASTM International and International Organization for Standardization (ISO). However, significant differences occur in Rockwell hardness tests depending on whether a steel or WC ball is used. In this paper, finite element analysis (FEA) is used to simulate the HR indentation process. The effects of four different sizes of steel and WC ball indenters on different Rockwell hardness scales are studied and compared with experimental measurements. This study provides important approximations of the differences between the performance of steel and WC Rockwell hardness indentors.