不均質層を有する金属材料の公称応力-ひずみ曲線に及ぼす初期残留応力の影響

抄録

Inhomogeneity and initial residual stress are considered to be the important factors controlling the fatigue fracture of laminated inhomogeneous metals such as induction hardened steels and carburized hardened steels. It is important to discuss quantitatively the relationship between these two macroscopic factors and cyclic plastic strain connected with fatigue life, on the basis of the valid relationship between stress and strain of laminated inhomogeneous metals.
The effects of inhomogeneity and initial residual stress on the nominal stress-strain curve were experimentally discussed from the tensile tests of the clad plates composed of low carbon steel and medium carbon steel. Some specimens were quenched in oil and others were successively tempered for the purpose of separating the above fundamental two factors. The analytical results of elasticity at the hardened part and plasticity at the softened part were compared with the experimental results. The problems concerning the biaxial residual stress and the hysteresis loop of laminated inhomogeneous metals were discussed analytically.