Clamped straight rod small sample creep testing method and apparatus thereof

Abstract

The invention provides a clamped straight rod small sample creep testing method and an apparatus thereof. The testing apparatus comprises a heating module, a loading module, a clamping module, a displacement measuring module and an external support; and the testing method comprises the following steps: designing and making a clamped straight rod small sample, carrying out multiple creep tests of a material at a same temperature under different loads, establishing a steady state creep rate curve, obtaining a Kachanov-Rabotnov creep damage constitutive equation, and adopting a finite element to carry out parameter optimization. The small sample creep testing method provided by the invention solves the problems of difficult data parse and many testing influence factors of present small sample technologies, has the advantages of simple operation, high testing precision and low cost, and provides basic data for the exploitation of a new material, the high-temperature integrity evaluation of a service member and the performance evaluation of an irradiated material.

Description

technical field [0001] The invention relates to a creep test method for a small straight bar sample, in particular to a test method for testing the creep performance of a material by using a small straight bar sample fixed. At the same time, it also relates to a device for performing a creep test of a small sample of a fixed straight bar. Background technique [0002] With the rapid expansion of high-energy industries such as thermal power, nuclear power, and petrochemicals, in order to improve the energy efficiency of equipment and systems, process machinery and equipment such as production, preparation, and storage are developing in the direction of high parameters such as high temperature and high pressure. Therefore, the structural integrity of mechanical equipment that has served in high-temperature and high-pressure environments for a long time plays an extremely important role. [0003] At present, the common method to predict the safety and remaining life of high-te...

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Problems solved by technology

For the first type of sample, the processing process needs to use electron beam welding technology to weld the test material with the clamping end, the manufacturing process is complicated, the cost is high, and the deformation measurement is difficult during the test

For the small punch creep test technology, it is widely used in the prediction of the remaining life of high temperature structures and materials, although the guidelines for small punch creep test methods have been published in Europe "CEN CWA156272006 Part A: A Code of Practice for Small Punch Creep Testing", but it is not a mandatory standard. There is no standard for small-punch creep test technology in China. Due to the complex deformation and many nonlinear factors of the small-punch specimen during the creep test, it is difficult to analyze the test data. The correlation with the traditional uniaxial test is mostly empirical, semi-empirical and numerical fitting formulas, which limits the popularization and application of this method

The indentation creep test is a local test method, which has an analytical correlation with the traditional test method, and the creep deformation data of the material can be obtained. However, due to the small indentation depth, in order to improve the deformation measurement accuracy, the test requires the indenter material to be The strength is much higher than that of the test material, which limits the application of this method in the creep performance test of high-strength materials; at the same time, because the indentation creep test method can only obtain the creep deformation data of the material, it is impossible to predict the remaining life

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