Monotonic and cyclic stress-strain behavior and strain-life resistance of cast 8630 (Mn. modified) at 254 ±5 BHN are reported. The material exhibits an engineering ultimate strength of 114 ksi, which is approximately 10% lower than a comparable wrought steel, and a comparatively low ductility of 17%. Cyclic softening of this cast alloy results in a cyclic yield strength (0.2% offset) of 80 ksi, whereas its monotonic yield strength is 103 ksi. Initial precycling of axially loaded fatigue specimens appears to decrease the fatigue life significantly. However, no general trend is exhibited when compared to non-precycled results. The fatigue performance of the cast steel is shown to be much poorer than would be obtained for a wrought steel with similar monotonic tension properties.
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