中高温における球状黒鉛鋳鉄の疲労き裂進展下限界

概要

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The in-plane bending fatigue tests were carried out on FCD 450 at elevated temperatures up to 723 K. The threshold stress intensity range ΔK_<th> and its effective values ΔK_<effth> were observed as a function of the temperature T. Plots of ΔK_<effth> and T revealed that ΔK_<effth> remained constant up to 623 K and then decreased to a value about 28% lower at 723 K. The ΔK_<th>-T relations showed that ΔK_<th> remained constant in the range of 473 K to 723 K, its value being about l0% lower than that at room temperature. While the ΔK_<effth> value at 723 K decreased by 28% lower than that at 623 K, there were no significant differences between the ΔK_<th> value at 723 K and that at 623 K. It appears that the rise of closure level K_<cl> induced by the high-temperature oxide on fracture surface results in the apparent increase in ΔK_<th> value at high temperature such as 723 K.
一般社団法人日本機械学会の論文
1995-02-25