Failure study of pneumatic rock drill piston

Abstract

In this study, the fracture of piston for rock drill produced from case hardening steel is investigated. In order to study the causes of the fracture, specimens prepared from the damaged pistons were subjected to experiments such as hardness, chemical analysis and metallurgical tests. The effect of microstructure on the fracture was also considered. The detailed metallurgical analysis was conducted on the fractured pistons and compared with the unfailed pistons in service. Results showed that the obtained pistons hardness values were lower than the values stated in the literature. Geometrical analysis of the pistons revealed that early failure of the structure started from a notch by which stress concentrations are created at the end of the threaded region. © 2005 Elsevier Ltd. All rights reserved.