过热器和再热器氧化皮开裂与剥落的预测与控制

Prediction and Control of Scale Cracking and Exfoliation on Superheater and Reheater Tube Steels

建立了应用于过热器和再热器的铁素体钢和奥氏体不锈钢管蒸汽侧氧化皮发生开裂和剥落时的临界应变随氧化皮厚度变化的模型,根据临界温度降幅与临界应变的关系,得到临界温度降幅与氧化皮厚度的关系。铁素体和奥氏体不锈钢管的氧化皮发生开裂和剥落时的临界应变均随氧化皮厚度增大而减小。公开发表的氧化皮厚度及其应力与所建立模型的临界值相吻合。氧化皮发生开裂和剥落时的临界温度降幅随氧化皮厚度的增大而减小,严格控制过热器和再热器管中的蒸汽温度波动是预防氧化皮剥落的有效方法。

Model of the elastic strain as a function of scale thickness to describe scale exfoliation for both ferritic and austenitic steels applied in superheater and reheater is developed,and the relationship between critical temperature drop and scale thickness is obtained based on the function between elastic strain and critical temperature drop.Results indicate that elastic strain decreases as the scale thickness increases.The scale thickness and strains resulting from the published data are in accordance with the diagram due to the model.The critical temperature drop decreases as the scale thickness increases,consequently strict control of the steam temperature perturbation is an effective method to suppress scale exfoliation.