Method of suppressing fatigue crack growth due to rolling of railroad vehicle wheels

摘要

PROBLEM TO BE SOLVED: To propose a technique for suppressing the growth of fatigue cracks in an axle center direction due to rolling generated in a heavy-duty freight car. SOLUTION: When a rolling fatigue crack 3 is present in a rim portion 1a of a wheel 1 of a railroad vehicle, the rolling fatigue crack 3 is a method of suppressing the growth of the rolling fatigue crack 3 toward the center of the axle. The contact position between the rim portion 1a of the wheel 1 and the rail 6 in the axle direction is 1) so as to be near the tip 3b on the anti-flange side of the rolling fatigue crack or on the anti-flange side of the tip 3b. 2) The rolling fatigue crack 3 is located within a range separated by an appropriate number of distances from the tip 3b on the anti-flange side of the rolling fatigue crack 3 on the flange side according to the axial length of the rolling fatigue crack 3. To. _{Alternatively} , 3) the mode I limit value ΔK _Ith of the material forming the wheel is made larger than the mode II crack growth limit value ΔK _IIth . [Selection diagram] Fig. 6