Method used for predicting creep life of heat-resisting alloy

A technology of creep life and heat-resistant alloys, applied in the direction of applying stable tension/pressure to test the strength of materials, etc., to achieve the effect of low error rate

Active Publication Date: 2017-04-19
SHENYANG POLYTECHNIC UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But in fact, the creep failure of materials does not only depend on the internal structure changes, surface oxidation, cor

Method used

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  • Method used for predicting creep life of heat-resisting alloy
  • Method used for predicting creep life of heat-resisting alloy
  • Method used for predicting creep life of heat-resisting alloy

Examples

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Embodiment 1

[0057] This example is a method for predicting the creep life of 403Nb steel at 600°C and 180MPa. Proceed as follows:

[0058] First, according to the "GB / T4338-2006 High Temperature Tensile Test Method for Metal Materials", a sheet-shaped "I"-shaped sample with a cross-section of 2.5mm×4.5mm and a gauge length of 14mm was used to measure the tensile strength σ of 403Nb steel at 600°C. b According to the "GB / T2039-2012 Metal Material Uniaxial Tensile Creep Test Method", a single-head testing machine is used to measure the tensile strength of 403Nb steel under 600°C, 240MPa, 250MPa, 260MPa, and 270MPa stresses. Tensile creep life, respectively: 240h, 211h, 190h, 170h; through the prediction model of creep life The least square method is used to fit the above creep test data to determine the parameter δ i (i=1,2,3,4) value: 0.0030,0.0260,0.0291,1.4170; In the formula: t r is the creep life, σ is the stress. The average fit error was 0.021%. Such as figure 1 Shown are the ...

Embodiment 2

[0063] This example is a method for predicting the creep life of HP40 alloy at 900°C and 35MPa. Proceed as follows:

[0064] First, according to the "GB / T4338-2006 High Temperature Tensile Test Method for Metal Materials", a sheet-shaped "I"-shaped sample with a cross-section of 2.5mm×4.5mm and a gauge length of 14mm was used to test the tensile fracture of the HP40 alloy at 900°C Intensity σ b It is 200MPa; according to "GB / T2039-2012 Metal Material Uniaxial Tensile Creep Test Method", a single-head testing machine is used, and the sample specification is the same as above, to measure the tensile creep of the alloy at 900°C, 40MPa, 45MPa, 50MPa stress The service life is respectively: 362h, 177h, 89h; through the prediction model of creep life The least square method is used to fit the above creep test data to determine the parameter δ i (i=1, 2, 3, 4) values: 5.9255e-004, 0.0854, -0.0183, 1.7774; as figure 2 Shown are the fitting curves of HP40 alloy 900°C and differen...

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Abstract

The invention provides a method used for predicting the creep life of heat-resisting alloy. According to the method, a creep life predicting model is established on the foundation of Arrhenius law; tensile creep life data at different stress at a certain temperature is predicted via fitting of the creep life predicting model, model parameter values are determined, a relationship formula of the creep life at a prediction temperature with the stress is obtained, and creep life prediction is carried out based on the relationship formula. In establishment of the creep life predicting model, action of high temperature strength of alloy materials on creep performance and influence factors of stress on creep deformation mechanism are taken into consideration fully, so that obtained results are more close to practical data, and creep life prediction accuracy is increased obviously. It is shown by results of creep life prediction tests of a plurality of materials that under experiment conditions, the prediction error of the method is reduced by one magnitude order in comparing with Arrhenius law and Larson-Miller method.

Description

technical field [0001] The invention belongs to the research field of high-temperature mechanical properties of metal materials, and relates to a method for predicting the creep life of heat-resistant alloys. Background technique [0002] Creep life is one of the important properties of heat-resistant alloys. Accurately predicting the creep life of heat-resistant alloys is the key to ensure safe production and improve production efficiency. The equation of Arrhenius law on the relationship between creep life and stress is: [0003] t r =k 0 exp(k 1 σ) (1) [0004] In the formula: t r is the creep life; k 0 、k 1 is the material constant; σ is the stress. The formula of this law has a simple structure and few parameters, but its scope of application is relatively limited. [0005] At present, the most widely used creep life prediction method is the time-temperature parameter method represented by the Larson-Miller method. In this method, the creep temperature, stress...

Claims

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Application Information

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IPC IPC(8): G01N3/18
CPCG01N3/18
Inventor 尚丽娟鲍识同
Owner SHENYANG POLYTECHNIC UNIV
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