阅读说明：本技术 一种高温部件持久小载荷删除谱确定方法 (Method for determining lasting small-load deletion spectrum of high-temperature component ) 是由 赵丰塬 于 2021-07-15 设计创作，主要内容包括：本发明公开了一种高温部件持久小载荷删除谱确定方法,涉及高温部件持久小载荷删除谱确定技术领域,具体为一种高温部件持久小载荷删除谱确定方法,包括以下步骤：S1、材料高温持久试验；S2、持久载荷阈值应力确定；S3持久小载荷删除谱确定方法。该高温部件持久小载荷删除谱确定方法中,只需进行高温持久试验,获得一系列同一温度不同应力条件下的最小蠕变速率,即可确定不同温度下的阈值应力,所需参数少,试验简单,成本低,并可应用于工程中常见的沉淀强化合金、固溶强化合金等材料,适用性强。(The invention discloses a method for determining a lasting small load deletion spectrum of a high-temperature component, which relates to the technical field of determining the lasting small load deletion spectrum of the high-temperature component, in particular to a method for determining the lasting small load deletion spectrum of the high-temperature component, and comprises the following steps: s1, performing a material high-temperature endurance test; s2, determining the endurance load threshold stress; s3 persistent small load deletion spectrum determination method. According to the method for determining the lasting small load deletion spectrum of the high-temperature component, threshold stress at different temperatures can be determined only by performing a high-temperature lasting test to obtain a series of minimum creep rates at the same temperature under different stress conditions, the required parameters are few, the test is simple, the cost is low, and the method can be applied to materials such as common precipitation strengthening alloy and solid solution strengthening alloy in engineering and has strong applicability.)

1. A method for determining a lasting small load deletion spectrum of a high-temperature component comprises the following steps:

s1, performing a material high-temperature endurance test;

s2, determining the endurance load threshold stress;

s3 persistent small load deletion spectrum determination method.

2. The method for determining the lasting small load deletion spectrum of the high-temperature component as claimed in claim 1, wherein: in the step S1, in the high-temperature endurance test of the material, the adopted test apparatus comprises a creep testing machine, endurance tests with different stress levels are carried out at the same temperature, and the minimum endurance load corresponding to the different stress levels is obtainedRate of creep

3. The method for determining the lasting small load deletion spectrum of the high-temperature component as claimed in claim 1, wherein: in the step S2, determining the endurance load threshold stress, based on the minimum creep rate data, using the formulaEstablishing a relation among the minimum creep rate, the stress and the threshold stress so as to obtain threshold stress levels corresponding to different temperatures;

wherein A is a constant, σ is stress, σ is_thIs the corresponding threshold stress level at that temperature.

4. The method for determining the lasting small load deletion spectrum of the high-temperature component as claimed in claim 1, wherein: in the method for determining the persistent small load deletion spectrum in the step S3, based on the threshold stress level obtained in the step S2, the persistent load smaller than the threshold stress in the original load spectrum is regarded as the small load, and then the small load is deleted, so that the persistent small load deletion spectrum is finally obtained.

Technical Field

The invention relates to the technical field of determination of a high-temperature component lasting small load deletion spectrum, in particular to a method for determining a high-temperature component lasting small load deletion spectrum.

Background

For high-temperature materials such as aero-engines, gas turbines, power station hot end components and the like, which work under high-temperature and high-stress conditions for a long time, failure is easy to occur under the long-term action of a lasting load, so a service life evaluation test must be carried out according to the service load condition of the materials to determine the service life of the materials. However, it is known from the actual service load spectrum that the high-temperature component is subjected to the action of the lasting small load which has no influence or little influence on the service life for a long time, and if the original load spectrum is adopted for testing, the defects of long test period, high cost and the like exist, so that the lasting small load which has no influence or little influence on the service life must be deleted to obtain a lasting small load deletion spectrum, and the deletion spectrum is used for carrying out a service life evaluation test.

The method generally adopted at present is to regard the load state with the ratio of the retention time of the lasting load to the creep life of the load state being less than 0.01 percent as the lasting small load, and delete the lasting small load and compile a small load deletion spectrum. Obviously, the method has no scientific theoretical basis and has the defect of serious engineering experience.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for determining a lasting small-load deletion spectrum of a high-temperature component, which solves the problems in the background art.

In order to achieve the purpose, the invention is realized by the following technical scheme: a method for determining a lasting small load deletion spectrum of a high-temperature component comprises the following steps:

s1, performing a material high-temperature endurance test;

s2, determining the endurance load threshold stress;

s3 persistent small load deletion spectrum determination method.

Optionally, in the step S1, in the high-temperature endurance test of the material, the adopted test apparatus includes a creep test machine, and the endurance tests of different stress levels are performed at the same temperature to obtain minimum creep rates of the endurance loads corresponding to the different stress levels

Optionally, in the step S2, determining the endurance load threshold stress, based on the minimum creep rate data, using a formulaEstablishing a relation among the minimum creep rate, the stress and the threshold stress so as to obtain threshold stress levels corresponding to different temperatures;

wherein A is a constant, σ is stress, σ is_thIs the corresponding threshold stress level at that temperature.

Optionally, in the method for determining the persistent small load deletion spectrum in step S3, based on the threshold stress level obtained in step S2, the persistent load in the original load spectrum that is smaller than the threshold stress is regarded as the small load, and then the small load is deleted, so that the persistent small load deletion spectrum is finally obtained.

The invention provides a method for determining a lasting small load deletion spectrum of a high-temperature component, which has the following beneficial effects:

1. in the method for determining the lasting small load deletion spectrum of the high-temperature component, only a high-temperature lasting test is needed to obtain a series of minimum creep rates under the same temperature and different stress conditionsThe threshold stress at different temperatures can be determined, the required parameters are few, the test is simple, and the cost is low.

2. The method for determining the lasting small-load deletion spectrum of the high-temperature component can be applied to materials such as common precipitation strengthening alloy and solid solution strengthening alloy in engineering, and has strong applicability.

Drawings

FIG. 1 is a schematic diagram of a method for determining threshold stress at 600 ℃ according to the present invention;

fig. 2 is a flow chart of the persistent small payload erasure spectrum determination of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Embodiment 1

Referring to fig. 1 to 2, the present invention provides a technical solution: a method for determining a lasting small load deletion spectrum of a high-temperature component comprises the following steps:

s1, material high-temperature endurance test: the adopted test apparatus comprises a creep testing machine, a plurality of groups of endurance tests with different stress levels are carried out at the same temperature, generally 5-7 groups of stress levels can be selected at the same temperature, and the test can be stopped after the steady-state creep stage is started, so that the minimum creep rate of the endurance load corresponding to different stress levels is obtained

S2, determining the endurance load threshold stress: minimum creep rate data based on endurance loadUsing formulasEstablishing a minimum creep rateStress sigma and threshold stress sigma_thThe relationship between the temperature and the stress values of the two adjacent temperature zones is obtained, and then the threshold stress levels corresponding to different temperatures are obtained;

wherein A is a constant, σ is stress, σ is_thIs the corresponding threshold stress level at that temperature.

The specific calculation process of the threshold stress comprises the following steps:

first, multiplying both sides of the formula by 1/5 to the power yields:

then, linear fittingTest data, wherein the intercept between the fitted straight line and the X axis is the corresponding threshold stress at the temperature;

then, repeating the steps to obtain corresponding threshold stress levels at different temperatures, and obtaining threshold stress values at other temperatures in a linear interpolation mode;

s3, determining a persistent small load deletion spectrum: based on the threshold stress level σ obtained in step S2_thThe persistent load smaller than the threshold stress level in the original load spectrum can be regarded as the persistent small load, and then the persistent small load is deleted, and finally the persistent small load deletion spectrum is obtained.

Example II

As shown in the attached figures 1 to 2, the method for determining the permanent small load deletion spectrum of the nickel-based superalloy GH4169 material comprises the following steps:

step 1, carrying out high-temperature holding of GH4169 material at 600 ℃ under 6 groups of different stress levelsLong time test to obtain the corresponding minimum creep rate under different stress conditions of the temperature

Step 2, linear fittingThe test data, as shown in FIG. 1, the intercept of the fitted straight line and the X axis is the corresponding threshold stress at 600 deg.C, and the obtained threshold stress value is σ_th＝623MPa；

And 3, based on the threshold stress, the persistent load less than 623MPa in the original load spectrum can be regarded as the persistent small load, so that the persistent small load can be deleted, and finally the persistent small load deleted spectrum is obtained.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.