Standard Sample Package for Calibration of X-Ray Stress Measurement

The purpose of our study is to provide standard samples for X-ray stress measurement. Typically zero adjustment is performed by a stress free sample which is a fine powder of pure metal. However, if the sample has stress (not stress-free), the stress value obtained by measurement can contain the errors caused by each stress measurement instrument. To solve this instrumental error, we have created a standard sample package. The sample package includes the following three samples. 1) Fluorescent powder to confirm the beam position and size. 2) Iron powder (particle size 6-8μm) to calibrate the zero-stress. 3) Bulk iron material which has approx. -100(MPa) of residual stress. Each sample has been laid out in a 6mm thick plate, and each sample can be selected by sliding the plate manually. By measuring the bulk material and the powder, correction and calibration of the stress measurement instrument is possible. The manufacturing process employed in this study has confirmed that the iron bulk material does not have residual stress and FWHM changes over time in the past 20 years. Therefore, the standard sample can be used semi permanently by adequate management. Correction of instrument by using this standard sample package increases the reliability of X-ray stress measurement method which will help to employ it in a wide range of practical uses.