Nondestructive Testing of Cylindrical Conducting Specimens Using a Direct Current Conduction Method. (Paper D-30)

摘要

The direct current conduction method may be used for the nondestructive testing of cylindrical conductor samples by means of a convenient measuring device, which consists of two contact electrodes for adduction of the electrical current to the sample (current contacts) and of two pairs of contact electrodes for measuring the small resulting voltage (voltage contacts). The comparison between the ratio of the electrical voltages measured at a given current, on the two pairs of voltage contacts and the calculated value of that ratio for a defectless sample, permits the evaluation of the kind and size of the defects existing in the conducting cylindrical sample. By rotating the sample as against the measuring device, complementary information concerning the shape and position of the flaws can be obtained.