ボイラ用低合金鋼の溶接熱影響部粗粒域クリープ損傷評価法 : "最大ボイド粒界占有率パラメータ法"の提案

概要

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Through investigations of the deterioration of serviced boilers and through time series investigations involving serviced-size creep rupture tests, it has been verified that damage tends to progress locally in the coarse-grain areas of heat affected zones of welded low-alloy boiler steel ; in other words, void development and interconnection progresses noticeably starting from specific grain boundaries. Focusing on this aspect, a "Maximum Fraction of Voids on the Grain boundary Line Parameter (M Parameter) Method" is proposed here as a new method of evaluating creep damage. Using this method, the authors quantified void-induced damage and summarized its relationship with the Creep Life Fraction(t/t_r). The results showed that a distribution was found along a gentle convex curve. Sensitivity and accuracy comparisons made with the conventional void area ratio method verified that this new method reacts with good sensitivity and produces accurate results pertaining to the consumed service life. In short, this new evaluation method is easier to use than the conventional method and is highly reliable.
一般社団法人日本機械学会の論文
2000-08-25