Abstract

A previously developed contactless method to measure the resistivity of metals at high temperatures has been extended for metal sheets. The theoretical basis of the method has been augmented by solving the problem of power input to a sample in the form of a thin-walled cylinder under inductive heating. Essentially, the method consists in measuring electromotive forces (EMFs) induced by a high-frequency electromagnetic field in two circular loops with different diameters that are arranged coaxially to the cylindrical sample. The formula derived for the power introduced into a thin-walled cylinder has made it possible to find a relationship between the resistivity of the sample and EMF. From the experimental values of the EMF, the resistivity of the sample and, accordingly, the power input to the sample have been determined. This has allowed us to determine the integral hemispherical emissivity factor of the sample. Data for experimentally checking the method using a thin-walled niobium cylinder are presented. They agree with those obtained by other authors to within 3%, which makes this method promising for practical application. Techniques for conducting necessary experiments and processing experimental data are exemplified.

中文翻译：

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高温下钣金电阻率的非接触式测量

摘要

先前开发的用于在高温下测量金属电阻率的非接触式方法已扩展到金属板。通过解决在感应加热下以薄壁圆柱体形式输入到样品的功率问题，增强了该方法的理论基础。本质上，该方法包括测量由高频电磁场在两个直径与圆柱样品同轴排列的不同直径的圆形环中感应的电动势（EMF）。推导到薄壁圆柱体中的功率的公式使得找到样品的电阻率和EMF之间的关系成为可能。根据EMF的实验值，可以确定样品的电阻率，从而确定输入样品的功率。这使我们能够确定样品的积分半球发射率因子。提供了使用薄壁铌圆柱体通过实验检查该方法的数据。它们与其他作者所获得的结果相吻合在3％之内，这使该方法具有实际应用前景。以进行必要实验和处理实验数据的技术为例。