2 相ステンレス鋼の熱処理による機械的性質の変化(<特集>ステンレス鋼)

概要

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The effect of heat treatment on the mechanical properties of Fe-25Cr-6Ni alloy has been investigated, and the results are summarized as follows. (1) In case of aging at 475-525℃, the tensile strength and 0.2% proof srtess increase continuously with aging time owing to the precipitation of Cr-rich phase in ferrite matrix. In spite of the decrease in elongation, the reduction of area shows an approximately constant value of 60-70%. (2) Heating at 650-800℃ produces the α-γ transformation and proof stress decreases with the increase of γ content. The tensile strength that is affected by work hardening of γ phase during the deformation does not vary in parallel with the proof stress. (3) Charpy impact value decreases with aging time at 475-525℃. The testing temperature dependence of the Charpy impact valus is based on the raise in the transition temperature due to the 475℃ embrittlement. (4) The prior α-γ transformation that produces an increase in γ content and an increase of Cr concentration in α phase leads to the reduction of susceptibility for 475℃ embrittlement. (5) It is observed that σ phase in two-phase stainless steel is formed by decomposition of high Cr ferrite phase into σ+γ, independently of Cr carbide.
社団法人日本鉄鋼協会の論文
1977-04-01