圧延鋼材の初期疲労破面形態に及ぼす層状組織の影響 表面の連続観察と破面との対応
Effect of Laminated Structure on Topography of Initial Fatigue Fracture Surface of Rolled Steel

Hironobu NISITANI, Masaharu KAGE
1984 Journal of the Society of Materials Science Japan  
Rotating bending fatigue tests were carried out, using the specimens cut out from a rolled The fatigue process on the specimen surface was observed successively by an optical microscope, and then the fracture surface of the same position was observed by a scanning electron microscope. The main results obtained are as follows: (1) The anisotropy of the fracture life is controlled by the difference in the process of crack initiation and propagation up to about 0.5mm. (2) Cracks in the rolling
more » ... in the rolling directional specimen originate at grain boundaries or the inside of grains in ferrite layers, while those in the thickness directional specimen originate at boundaries or near-boundaries between ferrite and pearlite in most cases, and the initial fatigue fracture surfaces are almost parallel to the maximum shearing stress plane. (3) The origin of fracture in the material with a large grain size is not so clear as in the case of the material with a small grain size.
doi:10.2472/jsms.33.252 fatcat:wfsn53lwdvckzfbll5vkzecfby