EVALUATION OF THE GIGA-CYCLE FATIGUE STRENGTH, CRACK INITIATION AND GROWTH IN HIGH STRENGTH H13 TOOL STEEL

摘要

The development and use of high performance steels, like tool steels, for advanced applications require reliable very high cycle fatigue (VHCF) properties. However, supporting knowledge and data are not available. This paper concerns VHCF properties of an H13 tool steel obtained during staircase testing using ultrasonic high frequency (20 kHz) test equipment. The evaluation of the fatigue mechanisms operating in the ultra high cycle regime during crack initiation and growth is made by means of high resolution FEG-SEM. The correlation is made between the VHCF performance of steel batches and their various inclusion contents. Comparison of VHCF results (10~9 load cycles) with HCF (2*10~6 load cycles) in conventional testing for an H13 steel is presented.