Metal wire expansion coefficient measuring method

Abstract

The invention relates to a metal wire expansion coefficient measuring method which includes steps of engraving grating fringe on a to-be-measured metal surface by means of grating engraving, acquiring a digital image of objective grating, making a reference grating, acquiring a digital image of the expanded objective grating, superposing the digital image of the reference grating and the digital image of the objective grating to obtain a first moire fringe, superposing the digital image of the reference grating and the expanded objective grating to obtain a second moire fringe, refining the first moire fringe and the second moire fringe by Fourier transform, filter treatment and extremum method to obtain a first refined isochromatic fringe and a second refined isochromatic fringe which is generated from the second moire fringe correspondingly, calculating slope and inclination of the corresponding isochromatic fringe by the least square method to obtain the variable of the inclination of the corresponding isochromatic fringe relative to an X-axis of the measuring system due to change of temperature, then calculating the calibrated slope and calculating the dependent variable on the condition that the temperature is equal to T2, and finally calculating expansion coefficient of materials.

Description

technical field [0001] The invention relates to a measurement technology, in particular to a measurement method for the linear expansion coefficient of a material. Background technique [0002] At present, there are many mature theories and methods for measuring the linear expansion coefficient of materials, such as strain gauge method, pressure gauge method, optical lever method, optical fiber displacement sensor method, interferometry, etc., but these measurement methods have certain bottlenecks. , firstly cannot be measured online. Since the above method must make the material into a specific sample and put it into a measuring instrument for measurement, online monitoring cannot be performed. In addition, the optical lever method and the interferometry require that the size of the measured material should not be too small, and the sample with a large size is easily affected by external factors, such as the inability to heat the measured material uniformly, which will aff...

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Problems solved by technology

[0002] At present, there are many mature theories and methods for measuring the linear expansion coefficient of materials, such as strain gauge method, pressure gauge method, optical lever method, optical fiber displacement sensor method, interferometry, etc., but these measurement methods have certain bottlenecks. , firstly cannot be measured online

Since the above method must make the material into a specific sample and put it into the measuring instrument for measurement, online monitoring cannot be performed

In addition, both the optical lever method and the interference method require that the size of the measured material should not be too small, and the sample with a large size is easily affected by external factors. For example, the measured material cannot be heated evenly, which will affect the accuracy of the measurement results.

In addition, the above method can only measure the coefficient of linear expansion in one-dimensional direction, which cannot meet the requirement of simultaneously measuring the coefficient of linear expansion in two-dimensional direction

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