Ultrasonic fatigue tests on bearing steel AISI-SAE 52100 at frequency of 20 and 30 kHz

摘要

Due to the increasing requirements in the market, engine components must have also an increasing life, which involves an improvement over 10~9 cycles in the fatigue strength of bearing steels, and sometimes even more. In order to achieve this improvement, this paper proposes a study of the fatigue behavior of the AISI-SAE 52100 between 10~5 and 10~(11) cycles. Most fatigue life tests are expensive and/or take long time, so in order to save time and money, the long-time fatigue life tests were carried out on a piezoelectric system built in our laboratory. These tests were carried out using two different ultrasonic machines which work at frequencies of 20 and 30 kHz, respectively, at room temperature. The conventional fatigue test was carried out on the servo-hydraulic equipment at 35 Hz. This test was conducted with symmetric cycle stress R = -1. Three different geometric types of specimen were used, as well as, the smooth specimens for testing at 20 kHz which were machined from three different manufacturers. Finally, one proposal of this paper is to make a comparison between our data in tension-compression and some results of Japanese researchers obtained using rotating bending fatigue systems.