Specimen for rotary bending fatigue test, evaluation method of fatigue characteristics using it, and shipping method of steel materials using the evaluation method

摘要

PROBLEM TO BE SOLVED: To measure a fatigue crack growth rate in a short time and by an inexpensive means, a test piece for a fatigue test, and a method for evaluating fatigue characteristics using the test piece (specifically, measurement of the fatigue crack growth rate). Method) and a method of shipping the steel material using the evaluation method in the steel material manufacturing process. SOLUTION: A round bar-shaped parallel portion having a diameter D of 4 to 18 mm and a length L of 20 to 80 mm is provided, and a D / L value is 0.5 or less, and a notch is formed at one position of the parallel portion. Perform a rotary bending fatigue test using a test piece for a rotary bending fatigue test provided with. [Selection diagram] Fig. 1