Effect of single initial overload and mean load on the low-cycle fatigue life of normalized 300 M alloy steel

Investigation of the Axial and Torsional Low-Cycle Fatigue Properties of Notched High Strength Steels for Application to Landing Gear Fuse Pins

“…As per ASTM E8 and ASTM A370, the reported strengths for AISI 4340 were rounded to the nearest 5 MPa, the reported strengths for 300M were rounded to the nearest 10 MPa, the elastic modulus for both materials was rounded to the nearest 10 GPa, and the percent reduction in area for both materials was rounded to the nearest percent. The mechanical properties for both the 4340 and the 300M were consistent with published values (Bassindale et al, 2020;MatWeb, n.d.). A complete comparison is included in the Appendix for reference.…”

“…One unique property of the SWT damage parameter is that, for a given fatigue life in cycles, the damage parameter is equal to the damage parameter under fully reversed loading conditions for the same fatigue life (Manson & Halford, 1981). The SWT model has successfully been applied to grey cast iron (Fash & Socie, 1982), hardened carbon (Fash & Socie, 1982;Koh & Stephens, 1991), and micro-alloyed steels (Bassindale et al, 2020;Colin et al, 2010;Farsetti & Blarasin, 1988), however it has demonstrated inaccuracies compared to other models when applied to AISI 4340 in the high-cycle fatigue regime (Badr & Ishak, 2021). One additional shortcoming of the SWT model is the inability to predict the effect of mean stresses on fatigue life when the maximum stress in a load cycle is compressive.…”

“…Regarding the effects of tensile overloads within the low-cycle regime, it was thought that plastic strains would inundate any beneficial compressive residual stresses imparted into the material. While the benefit of compressive residual stresses due to overload in HCF is well-established, Bassindale et al found that the effect of tensile and compressive residual stresses induced by overload had a negligible effect on the axial lowcycle fatigue life of normalized 300M steel (Bassindale et al, 2020). Further investigation should identify overload effects within the LCF regime and identify connections between material ductility and overload effects.…”

Residual Stress Relaxation in the Laser Welded Structure after Low-Cycle Fatigue and Fatigue Life: Numerical Analysis and Neutron Diffraction Experiment

“…where ε e is the elastic strain amplitude, σ f ′ is the fatigue strength, and b is the fatigue strength exponent [42]. The fatigue constants are obtained using regression analysis.…”

“…where ε p is the plastic strain amplitude, ε f ′ is the fatigue ductility coefficient, and c is the fatigue ductility exponent [42]. As shown in Figure 21, the elastic strain significantly affects N f above the transition life (N t ).…”