Power station boiler heating surface SA210C steel material state evaluation method

Abstract

The invention relates to a power station boiler heating surface SA210C steel material state evaluation method. Association between normal-temperature physical and chemical data and high-temperature creep data is established by associating room-temperature physical and chemical feature parameters and range, the high-temperature creep performance can be directly queried and called when the normal-temperature physical and chemical properties of a heating surface to be evaluated are matched with the associated feature parameters and range, therefore, repeated high-temperature creep performance testing is avoided, and the evaluation timeliness is improved. Meanwhile, localized creep damage mechanics and a multiaxial stress theory are adopted, an improved creep damage constitutive equation (that is, an improved K-R equation) under multiaxial stress is obtained, a creep critical damage value is obtained through data fitting according to the called high-temperature creep property data, therefore, a data standard is provided for heating surface state evaluation, and the evaluation accuracy is improved.

Description

technical field [0001] The invention relates to a method for evaluating the state of a power plant boiler material, in particular to a method for evaluating the state of an SA210C steel material on a heating surface of a power plant boiler based on a relational database based on a feature induction similarity theory and a numerical simulation based on high temperature creep damage mechanics. Background technique [0002] Creep failure of the heating surface of power station boilers due to material aging accounts for a large proportion of boiler accidents. It is an important means to ensure the safe operation of boilers by evaluating the material state and guiding maintenance and technical renovation work based on the evaluation results. The commonly used evaluation method for heating surface materials of utility boilers is mainly to conduct high-temperature creep tests on cut tubes on the heating surface, and then evaluate the material state by analyzing the test results. Co...

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Problems solved by technology

[0003] The existing evaluation methods have the following defects: First, it takes a long time to conduct high-temperature creep tests on materials, and the evaluation results cannot be given during the shutdown of the unit, so that the inspection and technical improvement of the heating surface cannot be guided in time, and many samples are required. ,costly

Secondly, there are limitations in the analysis methods of creep test results: the isothermal endurance strength method uses short-term data of high stress to linearly extrapolate long-term data of low stress, which is too sensitive to stress and does not consider creep deformation. There is a large gap in the state, especially the "inflection point" problem, which causes the inaccuracy of the extrapolated data; the quantitative assessment of creep metallographic damage by the creep damage method is limited by the site conditions of the power station and the development of non-destructive testing technology, and quantitative analysis The workload is heavy; the L-M formula method reduces the creep rupture time by increasing the test temperature, and uses the short-term test data to extrapolate the long-term data under a certain stress. The effect of metal structure changes cannot be replaced by time effects, and there is a lack of physical theoretical basis based on the creep fracture mechanism, and the simplified calculation of parameters also greatly affects the accuracy of the evaluation

Experimental research and data statistics show that there is a correlation between the physical and chemical properties of materials at room temperature and high temperature creep properties, but there are few studies on this

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