Exfoliation of steam-side oxide scale in heating surface occurring during load reduction severely affects the safety of thermal power plants. Through building the finite element model for steady stress analysis, the stresses in steam-side oxide scales during unit load drop were calculated and analyzed. Ferrite alloy represented by T91 and austenitic alloy represented by TP347H were investigated in this paper. Through analyzing each of the stress components and the von Mises equivalent stress, the change of the stresses in steam-side oxide scales for both ferrite alloy and austenitic alloy during unit load drop was revealed. The possible failure modes of steam-side oxide scales for both alloys were illustrated, and it could also be concluded that the exfoliation of steam-side oxide scales for ferrite alloy and austenitic alloy was more liable to occur in the final stage and in the initial stage of load reduction respectively.%电站锅炉高温受热面蒸汽侧氧化膜在机组停机降负荷时可能发生脱落,对安全性构成严重威胁.通过建立有限元分析模型,对锅炉停机过程中受热面蒸汽侧氧化膜内的应力进行了计算和分析.对铁素体合金和奥氏体合金进行了研究,其中铁素体合金以T91为代表,奥氏体合金以TP347H为代表.通过对各应力分量以及von Mises等效应力进行分析,揭示机组降负荷过程中两种合金管蒸汽侧氧化膜内应力的变化规律,阐明两种合金管蒸汽侧氧化膜可能的失效模式,同时得出了铁素体合金管和奥氏体合金管蒸汽侧氧化膜分别在负荷降低后期和初期容易发生脱落的结论.
展开▼
