Fundamental Study on Influence of Residual Stress Distribution on Fatigue Strength in ns Pulsed Laser Peening for Welded High-Strength Steel

Abstract:

Due to the recent increase in energy consumption, global environmental issues have attracted attentions in order to continue the sustainable development of society [1]. Currently, scrap-and-build becomes a mainstream in the field of constructions, which would use and /or dispose a large amount of materials. This situation results in massive energy consumption with a significant environmental impact [2]. Therefore, it is important to consider sustainable systems in the construction industry. In many countries, a lot of structures had been constructed during the period of rapid economic growth in the middle of the last century, and their constructions are reaching the end of their design lives. In particular, due to the significant increase in the number of automobiles, numerous cracks above the estimated numbers has been observed in the bridges of motorways. Therefore, the improvement of fatigue life is strongly required to keep a good condition of constructions for a long time. In addition, the nuclear power plant is one of important infrastructures in the modern society, and the proper maintenance of nuclear reactor has been required to ensure their safety after the accident at the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake. Stress corrosion cracking is considered as the most important damage event in the maintenance of nuclear reactor. Stress corrosion cracking occurs, when three factors are combined: tensile residual stress due to welding, material sensitization in the heat-affected zone, and the corrosive environment. In other words, eliminating one of these factors might prevent from generating stress corrosion cracks, and it is expected to extend the fatigue life of nuclear reactors [3]. Therefore, shot peening has been conventionally used as a method to reduce fatigue cracks, because the compressive residual stress can be obtained by the surface’s deformation generated by the high-speed impact of shot grain. However, quantitative control of residual stress is not easy in the shot peening process. Because the shot peening treatment involves the combinations of many factors in the collision between shot grains and the specimen’s characteristics, and the mechanism of micro-structural transformation is also important point to consider the process’s effect. In addition, shot grains possibly remains on the specimen surface, and the contamination of shot grains might deteriorate the functionality of metal surface [4].

• Periodical: Defect and Diffusion Forum (Volume 441)
• Pages: 61-68
• DOI: https://doi.org/10.4028/p-ii6dII
• Online since: March 2025
• Authors: Shoma Okura*, Hao Pan, Yasuhiro Okamoto, Akira Okada, Yoshihiro Sakino, Tomoharu Kato
• Keywords: Fatigue Life, High-Strength Steel, Laser Peening, ns Pulsed Laser, Residual Stress

References

[1] M. A. Bhuiyan, Q. Zhang, Vi. Khare, A. Mikhaylov, G. Pinter and X. Huang, Renewable Energy Consumption and Economic Growth Nexus-A Systematic Literature Review, Frontires in Environmental Science, Vol. 10 (2022) Airticle No. 878394.

DOI: 10.3389/fenvs.2022.878394

[2] M. A. T. Alsheyab, Recycling of Construction and Demolition Waste and Its Impact on Climate Change and Sustainable Development, International Journal of Environmental Science and Technology, Vol. 19 (2022), pp.2129-2138.

DOI: 10.1007/s13762-021-03217-1

[3] K. Nishikawa, Life Time and Maintenance of Highway Bridges, Journal of Japan Society of Civil Engineers, No. 501, (1994), pp.1-4 (in Japanese).

[4] H. Konishi, Y. Murakami, M. Kobayashi and T. Matsui, Mechanism of Creation of Compressive Residual Stress by Shot Peening and Its Effect on Fatigue Strength : Analysis of Residual Stress Produced By a Single Shot, Transactions of the Japan Society of Mechanical Engineers, Part A, Vol. 66, No. 650, (2000), pp.1847-1854 (in Japanese).

DOI: 10.1299/kikaia.66.1847

[5] T. Sano, T. Eimura, R. Kashiwabara, T. Matsuda, Y. Isshiki, and A. Hirose, Femtosecond Laser peening of 2024 Aluminum Alloy without a Sacrificial Overlay under Atmospheric Conditions, Journal of Laser Applications, Vol. 29, No. 1, (2017), pp."012005-1"-"012005-7".

DOI: 10.2351/1.4967013

[6] T. Kato, Y. Sakino and Y. Sano, Investigations for Improving Fatigue Strength by Low Energy Laser Peening via Bending Fatigue Test, Quarterly Journal of the Japan Welding Society, Vol. 40, No. 1, (2022), pp.56-65 (in Japanese).

DOI: 10.2207/qjjws.40.56

[7] A. Fujisawa and S. Nakao, Wavelength Characteristics of Laser Light Attenuation in Water, Transactions of the Institute of Electronics and Communication Engineers of Japan. B54, (1971), pp.365-370 (in Japanese).

[8] Y. Okamoto, N. Nishi, S. Nakashiba, T. Sakagawa and A. Okada, Smart, Laser Micro-welding of Difficult to weld Materials for Electronic Industry, Laser-based Micro- and Nano-Processing IX, Lasers and Application in Science and Engineering, Photonics West Conference 2015 (Proc. of SPIE Vol. 9351), (2015), pp. "935102-1"-"935102-9".

DOI: 10.1117/12.2076232

[9] K. Yoneyama and N. Ichii: Adaptation of HT780 with Reduced Residual Heat for Bridges, Kawada Giho, Vol. 14, (1995), pp.106-110.

[10] K. Tanaka: X-ray Stress Measurement by Cosα Method Using Two-dimensional Detector, Journal of the Socie-ty of Materials Science, Japan. Vol. 66, No. 7, (2017), pp.470-478.