低炭素鋼・中炭素鋼クラッド材の不均質性および残留応力分布に及ぼす熱処理の影響

抄録

The inhomogeneity and the residual stress are known to be important factors in determining the strength and the fracture of laminated inhomogeneous metals such as induction hardened materials, carburized hardened materials, superficially worked materials and other surface treated materials. This paper is concerned with the inhomogeneity and the residual stress after some heat treatments of a clad plate composed of low carbon steel and middle carbon steel, which can be regarded as an example of the above mentioned materials. The results obtained are as follows:
(1) The microstructure and the hardness change continuously at the boundary between two materials of the clad plate. The hardness distribution was explained quantitatively in terms of carbon diffusion at the boundary in the oil quenched clad plate.
(2) Tensile residual stress and compressive residual stress arise in the low carbon steel and in the middle carbon steel, respectively, of the oil quenched clad plate. The residual stresses become very small in the clad plate tempered at 400°C and disappear in the one tempered at 600°C.