Ultrasonic fatigue life of 40CrNiMoA (AISI4340) steel and its influencing factors Online publication date: Mon, 21-Nov-2005
by Honghong Shao, Guang Chen, Xinmin Luo
International Journal of Microstructure and Materials Properties (IJMMP), Vol. 1, No. 1, 2005
Abstract: The fatigue life of 40CrNiMoA (AISI4340) steel with different microstructures under ultrasonic fatigue loading (f = 20 KHz, R = –1) and its influencing factors were studied by the ultrasonic fatigue test. The results showed that the ultrasonic fatigue life of the specimen was markedly increased by surface treatment, and the ultrasonic fatigue life with the microstructures characterised by both strength and toughness was longer. The specimens' fatigue fractures were analysed by a scanning electron microscope. The results showed that crack initiation took place at the defect of the material surface at the ultrasonic fatigue loading and the crack propagated towards the inside. The fracture had both the features of cleavage and that of quasi-cleavage. The different microstructures of 40CrNiMoA steel have two different types of S–N curve: a continuously decreasing curve and a stepwise curve. The specimens continued to fail over 107 stress cycles.
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Microstructure and Materials Properties (IJMMP):
Login with your Inderscience username and password:
Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.
If you still need assistance, please email subs@inderscience.com
Our Blog 
Follow us on Twitter 
Visit us on Facebook