What is it about?
In an austenitic stainless steel type ASTM 904L that was cathodically hydrogenated, outgassed, and subsequently tested, the initiation of fatigue cracks was investigated. Tests were run with 50Hz combined loads (bending and torsion) and were paused at different periodsof fatigue life to allow scanning electron microscopy inspection of the gage surface of the samples (SEM). Slip marks were not visible on the surface of the hydrogenated and outgassed material, in contrast to the non-hydrogenated fatigued material. Its tired gage surface has consistently been related with the pre-existing hydrogen-induced fissures and has shown the "peeling off" of extremely thin layers in various locations from the start of the fatigue life. However, it was discovered that the major fatigue crack began subsurfacely, most likely along the boundary between the ductile material inside and the hydrogen-hardened exterior layer. It seems unlikely that the hydrogen-induced surface cracks will be employed as a tool to simulate the fatigue behavior of short fractures in austenitic stainless steels because they do not grow on their own.
Featured Image
Why is it important?
The objective was to determine if hydrogen-induced surface cracks that could be generated in a controlled manner might be used to simulate the fatigue behavior of small fractures in austenitic stainless steels.
Perspectives
According to the aforementioned studies, the fracture surface of the exhausted specimens made steps when they were hydrogenated, whereas the fracture surface of the non-hydrogenated ones was often flat. The simultaneous expansion of various surface fractures caused by hydrogen during fatigue of the various metals employed in the aforementioned researches was used to explain this. Later it was found that these facts might be explained by looking at the occurrence of fatigue fracture initiation on hydrogenated and out-gassed samples in an austenitic stainless steel type ASTM 904L. To accomplish this was one of the paper's stated objectives.
Mustafa Sami Abdullateef
University of Technology
Read the Original
This page is a summary of: Study of Surface Hydrogenation Effect on Fatigue Crack Initiation in ASTM 904L Austenitic Stainless Steel Under Cyclic Loading (Bending-Torsion), European Journal of Control, June 2024, International Information and Engineering Technology Association,
DOI: 10.18280/acsm.480306.
You can read the full text:
Contributors
The following have contributed to this page
