Measurement of Cyclic Stresses in High Temperature Range Using Nickel Electroplating : 2nd Report, Examination of Applicable Temperature and Accuracy of Measured Values

Abstract

A fundamental research for measurement of cyclic stresses in high temperature range is performed by applying a Watts-type nickel electroplating. The following results are presented. For the plating solution and plating conditions used, the range of applicable temperatures is from room temperature to 190°C. Though the desirable number of repetitions N is in the range of (0.5∼4)×10⁶, it is more appropriate for the accuracy of measured values to set N= (2∼3)×10⁶. Adding a small quantity of gelatin to the nickel plating solution, the applicable temperature range is extended toward higher temperature side. As a result of measurement of the stress-concentration factor in a circular shaft with a flat part under torsion, the measured values at each testing temperature are in good agreement with the theoretical result and it is verified that the present technique has sufficient accuracy.