Stress Ratio Effect on Ratcheting Behavior of AISI 4340 Steel

5th National Conference on Processing and Characterization of Materials

Bharathi, K Divya^1 ; Dutta, K.^1

Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela

769008, India^1

关键词: Aircraft components;    Cyclic hardening;    Effect of stress;    Engineering materials;    Hardening behavior;    Life predictions;    Metallic material;    Strain accumulations;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/115/1/012016/pdf
DOI  :  10.1088/1757-899X/115/1/012016

来源: IOP

【 摘 要 】

Ratcheting is known as accumulation of plastic strain during asymmetric cyclic loading of metallic materials under non-zero mean stress. This phenomenon reduces fatigue life of engineering materials and thus limits the life prediction capacity of Coffin-Manson relationship. This study intends to investigate the ratcheting behavior in AISI 4340 steel which is mainly used for designing of railway wheel sets, axles, shafts, aircraft components and other machinery parts. The effect of stress ratio on the ratcheting behaviour in both annealed and normalised conditions were investigated for investigated steel. Ratcheting tests were done at different stress ratios of -0.4, -0.6 and -0.8. The results showed that the material responds to hardening behavior and nature of strain accumulation is dependent on the magnitude of stress ratio. The post ratcheted samples showed increase in tensile strength and hardness which increases with increasing stress ratio and these variations in tensile properties are correlated with the induced cyclic hardening.