Statistical Analysis and Fatigue Life Estimations for Quenched and Tempered Steel at Different Tempering Temperatures

Abstract

Abstract:In this paper, the statistical properties and fatigue life estimations of 0.44% carbon steel at different tempering temperatures are presented. The specimens were austenized at 900 • C for 10 min, quenched in water, tempered at different temperatures, and then machined to the design geometry and average surface roughness of R a = 0.4 µm. The effect of tempering temperature on the fatigue life of 0.44% carbon steel was investigated using 75 fatigue tests, divided into three groups at temperatures 500 • C, 600 • C, and 700 • C. S-N and P-S-N curves were established. Two methods of estimating the mean fatigue life are presented. One is based on dislocation dipole accumulation and Paris' law; another is based on the kriging model. Six more fatigue tests were carried out to validate the presented methods. Test results showed that the first method is superior to the second in terms of estimating accuracy from the validation datum. However, the second method could estimate the mean fatigue life of quenched and tempered 0.44% carbon steel with an average surface roughness of R a = 0.4 µm when the tempering temperature was set to a value other than 500 • C, 600 • C, or 700 • C, with no additional fatigue test needed.

The effect of surface roughness of the substrate on fatigue life of coated aluminum alloy by micro-arc oxidation

“…When low alternating stress is applied, the result of the fatigue life (Table 3) at s max ¼ 220 MPa and s max ¼ 240 MPa coincide well with 4. The resulting material constants are brought into the Basquin equation (Equation ( 2)) to obtain the S-N curve [34].…”

Mean Stress Effect on the Axial Fatigue Strength of DIN 34CrNiMo6 Quenched and Tempered Steel

“…Tests were stopped at a maximum fatigue life of 2 × 10 6 cycles, taking into account the recommendations for the number of cycles of the fatigue limit for this type of steel [39]. The full S-N curves (P = 50%) were adjusted with the well-known Basquin formulation in the form N = α•σ β (α and β values in Table 3) commonly used in modern fatigue investigations with quenched and tempered steels as in [40]. In Figure 5 the S-N curves for the different stress ratios are presented, showing a measurable effect of the mean stresses for all the range of fatigue lives: 2 × 10 4 < N < 2 × 10 6 cycles.…”

The Effect of Carburization and Repeated Heat Treatment with Different Solutions on the Fatigue Resistance of Medium Carbon Steel

“…The tempered samples were examined at various temperatures before being air-cooled to eliminate internal stresses and provide the appropriate strength to the revised steel, as well as to obtain a varied microscopic ratio for the aim of examining its influence on fatigue resistance [25]. An arithmetic analysis of Carbon steel with 0.44 percent stress life at different temperatures was demonstrated [26]. Sultan et al [27] concluded that the coldrolled sample had better mechanical characteristics than the received sample.…”