[Closed] Fatigue/endurance limit SG Iron

Ok looking into the fatigue/endurance limit of SG Iron specifically grade 450/10. Have found data that supports an approximate value of 0.4 * tensile strength so around the 180MPa mark which seems about right but without testing specimens I have been unable to find the exact endurance limit of this grade of iron. I have found the tested values of other grades. Anyone do material science or can point me in the direction of some papers that look at this grade? I don't want to commission specific tests as I am sure it has already been done!