Fatigue crack propagation tests were carried out along different orientations of a hot rolled SB49 steel plate with or without homogenized heat treatment. The as-received material showed directionality in fatigue crack propagation due to the effect of lamellar structure, while the homogenizing treatment made crack growth isotropic both macroscopically and microscopically. Fractographic examination revealed that the ordinary striation mechanism was predominant when the crack plane was normal to the lamellar structure as well as for any orientation of the homogenized structure. For the case where crack plane was parallel to the lamellar structure, however, sub-cracks initiated at the edge of MnS inclusions located ahead of the main crack, and each propagated independently by a striation mechanism to join with the main crack.
|Zairyo/Journal of the Society of Materials Science, Japan
|Published - 1984 8月
ASJC Scopus subject areas