Fine residual stress distribution measurement of steel materials by SOI pixel detector with synchrotron X-rays

TL;DR

This paper presents a rapid, non-destructive method for measuring detailed residual stress distributions in steel using SOI pixel detectors with synchrotron X-rays, enhancing precision and speed over traditional techniques.

Contribution

It introduces a novel application of SOI pixel detectors with synchrotron X-rays for high-resolution, fast residual stress mapping in metals, improving upon previous laboratory-based methods.

Findings

Successful 2D residual stress measurement with synchrotron X-rays

Comparison shows improved accuracy and sampling with synchrotron over laboratory setup

Demonstrated feasibility of fine-resolution stress distribution analysis

Abstract

Residual stress is an important factor governing evaluating and controlling the quality of metal materials in industrial products. X-ray measurements provide one of the most effective means of evaluating residual stress without destruction. In such measurements, the effects of residual stress on the crystal structure can be observed through the Debye ring deformation. In previous studies, we developed a residual stress measurement system based on the $cos \alpha$ method, using a two-dimensional (2D) silicon-on-insulator pixel (SOIPIX) detector known as INTPIX4. In a typical laboratory setup, this system requires only 1 second to measure a specified point. This is drastically faster than the conventional system based on the $sin^{2} \psi$ method, which requires more than 10 min, and the $cos \alpha$-based system using an imaging plate, which requires 1 min. Compared to other systems, it can evaluate the 2D distribution of residual stress faster and provide more detailed information for evaluating materials. We first attempted to measure the 2D distribution in a laboratory setup with a Cr X-ray tube (Cr K$\alpha$ 5.4 keV) and obtained satisfactory results. We subsequently took measurements using synchrotron monochromatic X-rays to determine the fine accuracy and fine sampling pitch distribution. In this paper, we report the results of the initial synchrotron experiment, including the residual stress distribution of the standard specimen obtained by the first prototype setup. Furthermore, we compare the synchrotron measurements with those from the laboratory.