Method for evaluating creep performance of T/P92 steel

Abstract

The invention discloses a method for evaluating creep performance of T / P92 steel. The method comprises the following steps of: (1) acquiring a plurality of pieces of strain data of a sample at temperature T and under strain sigma through high-temperature creep test for the creep performance under the conditions of temperature T and strain sigma; (2) selecting more than six groups of test conditions and performing the high-temperature creep test on a T / P92 steel sample until the sample is broken to acquire short-time strain data under each test condition; (3) fitting the short-time strain dataaccording to a theta parametric method model to acquire a material coefficient corresponding to each theta parameter; (4) extrapolating the theta parameter at the temperature T and under the strain sigma by using the material coefficient and the strain data; and (5) acquiring a creep curve equation of the T / P92 steel at the temperature T and under the strain sigma by using a result of the step (4), and thereby evaluating the creep performance of the corresponding steel grade. The result of the invention is excellently matched with the test data, so that the accuracy for predicting the third stage of a creep curve of the T / P92 steel by using the theta parameter method can be effectively improved. The method can be used for high-temperature duration test design and evaluation of long-time creep performance by using short-time test data.

Description

technical field [0001] The present invention relates to the evaluation of the creep performance of T / P92 ferritic heat-resistant steel, in particular, it relates to improving the deformation data of the short-time creep test of T / P92 ferritic heat-resistant steel in the range of 550-750°C A method for predicting the accuracy of the third stage of the creep deformation curve of the corresponding steel grade. Background technique [0002] A typical creep curve is divided into three stages: ① the deceleration deformation stage in the early stage; ② the uniform deformation stage in the second stage; ③ the accelerated deformation stage in the third stage. It is a common method to evaluate the creep performance of materials by predicting the creep curve of materials. Among these methods the θ The parameter method is widely used. It is a creep deformation estimation method based on the constant stress creep test. Its basic model is , where ε for the strain, t for time, θ 1...

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Problems solved by technology

However, related studies have shown that θ When the parametric method is used to predict the creep curve of T / P92 steel, the predicted strain values ​​of the first and second stages are in good agreement with the measured values. The value has deviated from

This deviation can lead to serious overestimation when predicting T / P92 creep rupture life

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