レールの腹部ぜい性き裂進展特性とその影響因子の解明

抄録

Propagation Characteristics of rail web-cracking has been discussed in connection with residual stress in rails. To clarify the effect of residual stress on rail web-cracking, several testing methods for rail web-cracking were examined first and a DWWT (Drop Weight Wedge Test) method with high accuracy and good reproducibility was newly proposed. Secondly, by using this test method, the rail web-cracking properties of several kinds of rails were evaluated. DHH rails and NHH rail which were hardened by heat-treatment showed better web-cracking properties than the standard carbon rail and low alloy rail which were straightened by a roller straightenner. This is caused by the differeces in distribution and longitudinal residual stress between the head and the base in rails.
Furthermore, the relationship between the propagation length of web-crack and the amount of opening value on cut mouth by saw cutting along the rail web was discussed.