Suppression of Helium Induced Cracking in Laser Repair Welding of Highly Irradiated Stainless Steels

JOURNAL OF NUCLEAR MATERIALS

卷:556

Article

Chen, Jian¹  Tatman, Jonathan²  Feng, Zhili¹  Miller, Roger¹  Curlin, Stephanie¹  Dai, Tao¹  Mao, Keyou¹  Sutton, Benjamin²  Frederick, Greg¹ 

[1] Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA

[2] Elect Power Res Inst, Charlotte, NC USA

关键词: Laser repair welding;    Irradiated materials;    Helium induced crack;   

DOI  :  10.1016/j.jnucmat.2021.153206

来源: Elsevier

【 摘 要 】

Welding repair of irradiated nuclear reactor materials such as austenitic stainless steels used for the re-actor internals has been challenging due to irradiation generated helium in the material matrix over an extended period of time. In this study, improved laser welding techniques, including the novel Auxiliary Beam Stress Improved (ABSI) technique that proactively manages the stresses during laser repair welding is investigated to substantially reduce or avoid the occurrence of intergranular helium-induced cracking (HeIC). Laser weld cladding, with and without ABSI technique, was applied to deposit weld metal on ir-radiated stainless steel (Type 304 L) blocks with various helium concentrations up to approximately 20 atomic parts per million (appm). Welded samples were cross-sectioned and analyzed using optical and electron microscopes. It was found that, with the improved laser welding techniques, no macroscopic (millimeter-sized) cracks were observed in any of the samples. Microscopic (less than 50 mu m) cracks were present in the heat affected zone. Statistical analysis on the sample with the highest helium con-centration (similar to 20 appm) reveals that the ABSI technique could effectively reduce the size and amounts of microscopic cracks. (C) 2021 The Authors. Published by Elsevier B.V.

【 授权许可】

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