Measurement of Electrical Resistivity by Means of the Closely Coupled Probes Potential Drop Technique and Its Application to Distinction of Alloy Steels

A method using more sensitive closely coupled probes for d-c potential drop technique is applied to distinction of alloy steels. The probes are synthesized to build a small sensor. Some alloy steels, which are different from each other in chemical composition, are tested in experiment. A simple equation of the potential drop for an uncracked plate is obtained. Using the equation, the electrical resistivity of the materials is calculated. It is found through multivariate analysis that the resistivity of the alloy steels correlates well with their chemical composition. As a result, it is verified that the closely coupled probes potential drop technique is useful for the evaluation of resistivity in a moment and the distinction of alloy steels.