An Automatic Ultrasonic Fatigue Testing System for Studying Low Crack Growth at Room and High Temperatures

Abstract

In this paper, an automatic ultrasonic fatigue testing system is presented, including a computer control and acquisition system, a video-camera-television system, an induction heating device, a magneto-strictive vibrator, and other electronic apparatus. The test machine controlled by an IBM PS/2 computer with analog to digital (A/D) and digital to analog (D/A) convertors runs at a very high frequency, about 20 kHz, and it carries out endurance tests and crack growth tests at room or high temperature. In this paper, a S-Ncurve for UDIMET 500 at room temperature and two fatigue crack growth rate (FCGR) curves in near-threshold regime for ASTROLOY at 20 and 400°C under ultrasonic fatigue testing are published.