Investigation of Fatigue Damage of Tempered Martensitic Steel during High Cycle Fatigue and Very High Cycle Fatigue Loading Using In Situ Monitoring by Scanning Electron Microscope and High?Resolution Thermography

Herein, the fatigue damage mechanisms of a low-alloyed 0.5 wt% carbon steel (50CrMo4) are examined in high cycle and very regime, taking into account different strength conditions. For this purpose, heat treatment material is conducted using two batches at tempering temperatures, which lead to hardnesses 37HRC 57HRC, respectively. The tests accounting for test frequencies f = 95 Hz 20 kHz, as well size effects. It found that behavior tempered 50CrMo4 can be subdivided type I (surface cracks) II (internal VHCF depending on condition. With aid situ equipment, influence microstructural banding local demonstrated by high-resolution thermography. By implementing an ultrasonic testing machine scanning electron microscope, development fine granular area (FGA) artificial defect vacuum atmosphere demonstrated.