Prediction method of creep incubation period with residual stress under plastic condition

Abstract

The invention discloses a prediction method for a creep inoculation period considering a residual stress under a plastic condition. On the basis of Davies work, the prediction model for the creep inoculation period considering the residual stress is provided. By means of a reference stress method, an elastic follow factor Z is introduced to calculate the creep inoculation period considering the residual stress. The residual stress is generated through pre-compression by using a compact tensile sample (CT), and a main load is applied to perform a creep test. The method has the beneficial effects that an original prediction model can be expanded into a model comprising the residual stress, and the simplified prediction method for the creep inoculation period under the plastic condition is provided, so that the creep inoculation period under the plastic condition can be concisely and effectively predicted in a structure.

Description

technical field [0001] The invention relates to engineering critical evaluation of creep incubation period of high-temperature structures containing residual stress under plastic conditions, which is to determine the creep crack initiation life of the high-temperature structure when surface cracks exist in the structure and are under plastic stress conditions. Background technique [0002] The coal-based energy structure is one of the main causes of smog in my country, and coal-fired power generation is currently the most important power generation method in my country, and this trend will exist for a long time. Therefore, in addition to changing the energy structure, developing efficient and clean ultra-supercritical (USC) units is one of the important ways to save energy and reduce emissions. However, the increase of parameters such as steam temperature and pressure has led to a very harsh service environment for the key high-temperature pipelines of the unit, especially c...

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Problems solved by technology

The creep incubation period is the longest stage in the creep process, and the accurate prediction of the incubation period is of great significance for the prediction of the creep life of high-temperature structures; the incubation period prediction model proposed by Davies et al. based on the ductile dissipation model considers The integrity of the stress change during the creep process, but the influence of the residual stress of the structure on the incubation period has not been studied; the residual stress widely exists in the high-temperature components processed and manufactured, and has a significant impact on the service life of the components

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