METHOD FOR EVALUATING FATIGUE STRENGTH OF FILLETED PORTION AND METHOD FOR EVALUATING ROLLING CONDITION OF FILLETED PORTION

PROBLEM TO BE SOLVED: To provide a method for evaluating the fatigue strength of a filleted portion, enabling the fatigue strength of the filleted portion for extracting a rolling condition to be evaluated at a comparatively low cost.SOLUTION: A method for evaluating the fatigue strength of the filleted portion of a crankshaft is provided that comprises the steps of: sampling a tabular test piece including a part of the filleted portion; and performing the fatigue test of the sampled test piece. The test piece has a central portion and a pair of gripping portions and satisfies the following conditions (A)-(C), and the fatigue test provides an axial force in the extending direction of the gripping portion of the test piece. (A) the average thickness t1[mm] of the central portion is 1 mm or more and 10 mm or less. (B) the maximum amount L [mm] of offset at the center in the thickness direction and the average thickness t1 of the central portion satisfy the following formula (1). 0.5