X-ray diffraction is widely used as a non-destructive method for measuring residual stress in crystalline materials, and is particularly useful as a technique for controlling residual stress that has been introduced during the heat treatment or surface treatment of metallic materials. Neutron stress measurement is gaining attention as an internal material measurement method. It complements the demerits of the X-ray method in that it measures stress in a very thin surface layer. The neutron stress measurement method, like the X-ray method, is based on the principle of crystal diffraction, and its penetration depth is about 1,000 times greater than that of the X-ray method and is suitable for measuring the inside of a material. This study investigated the residual stress measurement method using the sin2ψ method using shot-peened mechanical structural carbon steel. The non-destructive measurement using high-energy X-rays was compared with the residual stress measured using conventional laboratory X-rays, and the following results were obtained. The high intensity diffraction angles using highenergy X-rays are low, but can be measured with sufficient precision. Interpreting the three diffractions 633, 552, and 721 as a single diffraction profile allowed stress measurements to be made, and the calculated value was close to the weighted average of the intensity ratios. The results of the high-energy X-ray residual stress measurements were in good agreement with the results from laboratory X-rays, confirming the usefulness of this method as a non-destructive method of assessing stress deep inside materials.

Abstract
1. Introduction
2. Experimental Procedure
    2.1. Materials and specimens
    2.2. Stress measurement using characteristic X-rayCrKα
    2.3. Stress measurement using high-energy SR
    2.4. X-ray penetration depth and measured stressvalue
    2.5. Measurement of X-ray elastic constants
3. Results and Discussion
    3.1. Stress distribution under the surface of shotpeening
    3.2. X-ray elastic constants
    3.3. Non-destructive measurement of residual stressin shot peened materials
    3.4. Stress values calculated by the linear approximationof the sin2ψ method
4. Conclusion
References
Author Information

• Chang-Hwan Bae(Department of Information & Communication Engineering, Hoseo University, Asan 31499, Republic of Korea)
• Seung-In Lim(Department of ICT Automotive Engineering, Hoseo University, Dangjin 31702, Republic of Korea)
• Chang-Suk Han(Department of ICT Automotive Engineering, Hoseo University, Dangjin 31702, Republic of Korea) Corresponding author