Determination of strain-rate and temperature dependent high-speed steel material data via Fe analysis of repetitive impact test imprints

Abstract

A computational and experimental method is introduced for the mathematical description of stress–strain curves for high-speed steels dependent on strain-rate and temperature. The developed method is based on an FEM-supported evaluation of imprints created on the surface of HSS (high-speed steel) specimens subjected to repetitive impacts by a cemented carbide ball indenter. The experiments were performed at various impact times and temperatures. The quasi-static HSS material properties were determined using an FEM based evaluation of nanoindentation results carried out at various temperatures on the HSS specimens. In the conducted FEM calculations, the stress, strain, and stain-rate data for the cemented carbide ball indenter were taken from a recent publication. By simulating the impact test with a finite element model, the quasi-static HSS stress–strain data were proportionally adjusted by the stress augmentation ratio (SAR) until the calculated imprint depths converged with the measured ones at various temperatures and impact times. Hence, equations were developed describing SAR depending on the strain rate and temperature. Characteristic implementation examples of these equations to describe HSS stress, strain properties dependent on strain-rate and temperature are presented.

Keywords

• high-speed steel
• stress–strain
• strain rate
• temperature
• repetitive impact test