Fatigue crack growth rate of a low carbon microalloyed steel for elevated temperature application

Abstract

The operating temperature influence on the fatigue crack growth parameter, was analyzed by testing the chromium-molybdenum steel for elevated temperatores application of the new generation additionally alloyed with vanadium. The paper presents a comparison of the fatigue threshold value AKa, and the fatigue crack growth rate da/dN of the specimens cutting from pipe made of virgin steel, tested at room (RT) and operating (liT) temperatore of540 °C. The influence of the notch and crack initiation location, as well as the test temperature values, have a decisive effect on the fatigue threshold values AKth of the investigated steel. The macroscopic and microscopic specimens' fracture surfaces are also shown. Obtained results of fatigue crack growth parameter, correspond to the SEM micrographs of fractured surfaces.