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29 pages, 28581 KB

Open AccessEditor’s ChoiceReview

Peening Techniques for Mitigating Chlorine-Induced Stress Corrosion Cracking of Dry Storage Canisters for Nuclear Applications

by Subin Antony Jose, Merbin John, Manoranjan Misra and Pradeep L. Menezes

Materials 2025, 18(2), 438; https://doi.org/10.3390/ma18020438 - 18 Jan 2025

Cited by 3 | Viewed by 950

Abstract

Fusion-welded austenitic stainless steel (ASS) was predominantly employed to manufacture dry storage canisters (DSCs) for the storage applications of spent nuclear fuel (SNF). However, the ASS weld joints are prone to chloride-induced stress corrosion cracking (CISCC), a critical safety issue in the nuclear industry. DSCs were exposed to a chloride-rich environment during storage, creating CISCC precursors. The CISCC failure leads to nuclear radiation leakage. Therefore, there is a critical need to enhance the CISCC resistance of DSC weld joints using promising repair techniques. This review article encapsulates the current state-of-the-art of peening techniques for mitigating the CISCC in DSCs. More specifically, conventional shot peening (CSP), ultrasonic impact peening (UIP), and laser shock peening (LSP) were elucidated with a focus on CISCC mitigation. The underlying mechanism of CISCC mitigation in each process was summarized. Finally, this review provides recent advances in surface modification techniques, repair techniques, and developments in welding techniques for CISCC mitigation in DSCs. Full article

(This article belongs to the Special Issue Corrosion Mechanism and Protection Technology of Metallic Materials)

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14 pages, 15750 KB

Open AccessArticle

Mitigating Stress Corrosion Cracking of 304L and 316L Laser Welds in a Salt Spray through Micro-Shot Peening

by Chia-Ying Kang, Tai-Cheng Chen, Ren-Kae Shiue and Leu-Wen Tsay

Metals 2023, 13(11), 1898; https://doi.org/10.3390/met13111898 - 16 Nov 2023

Cited by 2 | Viewed by 2168

Abstract

Two austenitic stainless steel (ASS) plates, 304L and 316L, were cold-rolled (304R and 316R) with a 10% reduction in thickness and then subjected to laser welding. Cold rolling caused slight surface hardening and introduced residual tensile stress into the ASS plates. The susceptibility to stress corrosion cracking (SCC) of the welds (304RW and 316RW) was determined using the U-bend test pieces in a salt spray. To highlight the stress concentration at the weld’s fusion boundary (FB), the top weld reinforcement was not ground off before bending. Moreover, micro-shot peening (MSP) was performed to mitigate the SCC of the welds by imposing high residual compressive stress and forming a fine-grained structure. Cold rolling increased the susceptibility of the 304R specimen to pitting corrosion and intergranular (IG) microcracking. Moreover, pitting corrosion and SCC were found more often at the FBs of the 304RW. The corrosion pits of the peened 304RW (304RWSP) were finer but greater in amount than the those of the un-peened one. The results also indicated that the 316L ASS welds with MSP were resistant to the incidence of pitting corrosion and SCC in a salt spray. The better reliability and longer service life of dry storage canisters could be achieved by using 316L ASS for the construction and application of MSP on it. Full article

(This article belongs to the Special Issue Fusion Welding)

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21 pages, 14270 KB

Open AccessEditor’s ChoiceArticle

Effect of Laser Shock Peening on the Stress Corrosion Cracking of 304L Stainless Steel

by Young-Ran Yoo, Seung-Heon Choi and Young-Sik Kim

Metals 2023, 13(3), 516; https://doi.org/10.3390/met13030516 - 3 Mar 2023

Cited by 17 | Viewed by 3856

Abstract

Storage canisters used in nuclear power plants operating in seaside areas—where the salt content in the atmosphere is high—may be susceptible to chloride-induced stress corrosion cracking (CISCC). Chloride-induced stress corrosion cracking is one of the ways in which dry storage canisters made of stainless steel can degrade. Stress corrosion cracking depends on the microstructure and residual stress, and it is therefore very important to improve the surface properties of materials. Laser shock peening both greatly deforms the material surface and refines grains, and it generates compressive residual stress in the deep part from the surface of the material. This study focused on the effect of laser shock peening on the stress corrosion cracking of 304L stainless steel. The laser shock peening was found to induce compressive residual stress from the surface to a 1 mm depth, and the SCC properties were evaluated by a U-bend test. The results showed that the SCC resistance of laser-peened 304L stainless steel in a chloride environment was enhanced, and that it was closely related to grain size, the pitting potential of the cross section, and residual stress. Full article

(This article belongs to the Special Issue Feature Paper Collection of “Current Challenges in Corrosion Research”)

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14 pages, 9683 KB

Open AccessArticle

Effect of Laser Peening on the Corrosion Properties of 304L Stainless Steel

by Young-Ran Yoo, Seung-Heon Choi and Young-Sik Kim

Materials 2023, 16(2), 804; https://doi.org/10.3390/ma16020804 - 13 Jan 2023

Cited by 17 | Viewed by 2189

Abstract

Dry canisters used in nuclear power plants can be subject to localized corrosion, including stress corrosion cracking. External and residual tensile stress can facilitate the occurrence of stress corrosion cracking. Residual stress can arise from welding and plastic deformation. Mitigation methods of residual stress depend upon the energy used and include laser peening, ultrasonic peening, ultrasonic nanocrystal surface modification, shot peening, or water jet peening. Among these, laser peening technology irradiates a continuous laser beam on the surface of metals and alloys at short intervals to add compressive residual stress as a shock wave is caused. This research studied the effect of laser peening with/without a thin aluminum layer on the corrosion properties of welded 304L stainless steel. The intergranular corrosion rate of the laser-peened specimen was a little faster than the rate of the non-peened specimen. However, laser peening enhanced the polarization properties of the cross-section of 304L stainless steel, while the properties of the surface were reduced by laser peening. This behavior was discussed on the basis of the microstructure and residual stress. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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12 pages, 8162 KB

Open AccessReview

Application of the Advanced Surface Modification Process to the ASME Code Case for Sections III and XI of Nuclear Power Plants

by Sungwoo Cho, Hyun-Uk Hong, Nicholas Mohr, Marc Albert, John Broussard, Auezhan Amanov and Young-Sik Pyun

Metals 2020, 10(2), 210; https://doi.org/10.3390/met10020210 - 1 Feb 2020

Cited by 1 | Viewed by 3219

Abstract

The advanced surface modification process is known as a promising solution to improve the performance of machine components and systems, especially for vehicles, nuclear power plants, biomedical device, etc. There have been several successful applications of water jet peening and underwater laser peening to nuclear components in Japan since 2001 which resulted in inspection and repair cost savings. The prerequisite condition for the application of the advanced surface modification process to nuclear power plants is the approval of the American Society of Mechanical Engineers (ASME) Code Case, so performance criteria and requirements (PCRs) in the ASME Code Case for repair and maintenance of nuclear power components are explained. A challenging project to apply advanced surface modification processes, such as ultrasonic nanocrystal surface modification and air laser peening to new nuclear power plants and new canisters, was created with the goal to develop a technical basis and the PCRs for ASME Section III (New Manufacturing). The results of this work will be an ASME Section III Code Case which is currently in progress. An initial draft of the new Code Case with the intermediate results of this work is introduced. Four kinds of advanced surface modification processes are explained and compared briefly. Full article

(This article belongs to the Special Issue Advanced Surface Modification Technologies)

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13 pages, 4957 KB

Open AccessArticle

Improving Fatigue Performance of Laser-Welded 2024-T3 Aluminum Alloy Using Dry Laser Peening

by Tomokazu Sano, Takayuki Eimura, Akio Hirose, Yosuke Kawahito, Seiji Katayama, Kazuto Arakawa, Kiyotaka Masaki, Ayumi Shiro, Takahisa Shobu and Yuji Sano

Metals 2019, 9(11), 1192; https://doi.org/10.3390/met9111192 - 6 Nov 2019

Cited by 24 | Viewed by 4401

Abstract

The purpose of the present study was to verify the effectiveness of dry laser peening (DryLP), which is the peening technique without a sacrificial overlay under atmospheric conditions using femtosecond laser pulses on the mechanical properties such as hardness, residual stress, and fatigue performance of laser-welded 2024 aluminum alloy containing welding defects such as undercuts and blowholes. After DryLP treatment of the laser-welded 2024 aluminum alloy, the softened weld metal recovered to the original hardness of base metal, while residual tensile stress in the weld metal and heat-affected zone changed to compressive stresses. As a result, DryLP treatment improved the fatigue performances of welded specimens with and without the weld reinforcement almost equally. The fatigue life almost doubled at a stress amplitude of 180 MPa and increased by a factor of more than 50 at 120 MPa. DryLP was found to be more effective for improving the fatigue performance of laser-welded aluminum specimens with welding defects at lower stress amplitudes, as stress concentration at the defects did not significantly influence the fatigue performance. Full article

(This article belongs to the Special Issue Laser Shock Processing and Related Phenomena)

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