層状不均質性を伴う残留応力場の疲労き裂伝ぱ挙動

抄録

The clad plates composed of low carbon and high carbon steels were prepared in order to investigate effects of laminated inhomogeneity and residual stress distribution balanced along the thickness on fatigue crack propagation behavior. The fatigue crack propagation rates of the tempered clad plate without the residual stress were situated between those of both base metals, which showed a behavior based on the law of mixture. The fatigue crack propagation rates of the quenched clad plates with the residual stress were lower than those of both base metals under the same fatigue condition. This was because the crack opening displacement, even in unhardened parts with tensile residual stress, was suppressed by the crack front curved because of the residual stress field balanced along the thickness, in which the stress intensity factor due to the residual stress was estimated to be almost zero.