This article is
- freely available
Resistance Upset Welding of ODS Steel Fuel Claddings—Evaluation of a Process Parameter Range Based on Metallurgical Observations
Den-Service d’Etudes Mécaniques et Thermiques (SEMT), CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
Centre National de la Recherche Scientifique (CNRS), University Bordeaux, ICMCB, UPR 9048, F-33600 Pessac, France
Surface Analyses Departement, University Bordeaux, Placamat, UMS 3626, F-33600 Pessac, France
Author to whom correspondence should be addressed.
Received: 18 July 2017 / Accepted: 8 August 2017 / Published: 29 August 2017
Resistance upset welding is successfully applied to Oxide Dispersion Strengthened (ODS) steel fuel cladding. Due to the strong correlation between the mechanical properties and the microstructure of the ODS steel, this study focuses on the consequences of the welding process on the metallurgical state of the PM2000 ODS steel. A range of process parameters is identified to achieve operative welding. Characterizations of the microstructure are correlated to measurements recorded during the welding process. The thinness of the clad is responsible for a thermal unbalance, leading to a higher temperature reached. Its deformation is important and may lead to a lack of joining between the faying surfaces located on the outer part of the join which can be avoided by increasing the dissipated energy or by limiting the clad stick-out. The deformation and the temperature reached trigger a recrystallization phenomenon in the welded area, usually combined with a modification of the yttrium dispersion, i.e., oxide dispersion, which can damage the long-life resistance of the fuel cladding. The process parameters are optimized to limit the deformation of the clad, preventing the compactness defect and the modification of the nanoscale oxide dispersion.
ODS steel; PM2000; oxide dispersion strengthened; welding; resistance welding; fuel cladding; sodium fast reactor; dynamical recrystallization
This work is part of PhD between the Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) and the Commissariat à l’énergie atomique et aux énergies alternatives (CEA-Saclay). The PhD is part of a research program for materials suitable for Sodium Fast Reactor (SFR) financed by CEA, Areva NP (Areva Nuclear Power) and EDF (Électricité De France).
Fabien Corpace is the Ph.D. student. He wrote the paper, Arnaud Monnier, Jean-Pierre Manaud and Angeline Poulon-Quintin directed his work. Michel Lahaye performed the WDS experiments; Jacques Grall contributed to sample preparation.
Conflicts of Interest
The authors declare no conflict of interest.
- Dubuisson, P.; de Carlan, Y.; Garat, V.; Blat, M. ODS Ferritic/martensitic alloys for Sodium Fast Reactor fuel pin cladding. J. Nucl. Mater. 2012, 428, 6–12. [Google Scholar] [CrossRef]
- Yvon, P.; Le Flem, M.; Cabet, C.; Seran, J.L. Structural materials for next generation nuclear systems: Challenges and the path forward. Nucl. Eng. Des. 2015, 294, 161–169. [Google Scholar] [CrossRef]
- Hedrich, H.D. Joining of ODS-superalloys. In High Temperature Materials for Power Engineering Part 1; Bachelet, E., Ed.; Kluwer Academic Publishers: Liège, Belgium, 1990; pp. 789–799. ISBN 0-7923-0925-1. [Google Scholar]
- Wright, I.; Tatlock, G.; Badairy, H.; Chen, C. Summary of Prior Work on Joining of Oxide Dispersion-Strengthened Alloys, Task 8; Oak Ridge National Laboratory (ORNL): Oak Ridge, TN, USA, 2009. Available online: https://digital.library.unt.edu/ark:/67531/metadc932605/ (accessed on 8 August 2017).
- Seki, M.; Hirako, K.; Kono, S.; Kihara, Y.; Kaito, T.; Ukai, S. Pressurized resistance welding technology development in 9Cr-ODS martensitic steels. J. Nucl. Mater. 2004, 329–333, 1534–1538. [Google Scholar] [CrossRef]
- Ukai, S.; Kaito, T.; Seki, M.; Mayorshin, A.A.; Shishalov, O.V. Oxide Dispersion Strengthened (ODS) Fuel Pins Fabrication for BOR-60 Irradiation Test. J. Nucl. Sci. Technol. 2005, 42, 109–122. [Google Scholar] [CrossRef]
- Zirker, L.; Bottcher, J.; Shikakura, S.; Tsai, C.; Hamilton, M. Fabrication of Oxide Dispersion Strengthened Ferritic Clad Fuel Pins. In Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles, Kyoto, Japan, 28–31 October 1991. [Google Scholar]
- Zirker, L.; Tyler, C. Pressure Resistance Welding of High Temperature Metallic Materials. In Proceedings of the ANS Decomissioning, Decontamination & Reutilization Conference, Idaho Falls, ID, USA, 29 August–2 September 2010. [Google Scholar]
- De Burbure, S. Resistance Butt Welding of Dispersion-Hardened Ferritic Steels. In Proceedings of the Advances in Welding Processes 3rd International Conference, Harrogate, UK, 7–9 May 1974; pp. 216–228. [Google Scholar]
- De Burbure, S. Resistance welding of pressurized capsules for in-pile creep experiments. Weld. J. 1978, 57, 23–30. [Google Scholar]
- Shinozaki, K.; Kang, C.Y.; Kim, Y.C.; Aritoshi, M.; North, T.H.; Nakao, Y. The metallurgical and mechanical properties of ODS alloy MA 956 friction welds. Weld. J. 1997, 76, S289–S299. [Google Scholar]
- Chen, C.L.; Wang, P.; Tatlock, G.J. Phase transformations in yttrium–aluminium oxides in friction stir welded and recrystallised PM2000 alloys. Mater. High Temp. 2009, 26, 299–303. [Google Scholar] [CrossRef]
- Mathon, M.H.; Klosek, V.; de Carlan, Y.; Forest, L. Study of PM2000 microstructure evolution following FSW process. J. Nucl. Mater. 2009, 386–388, 475–478. [Google Scholar] [CrossRef]
- Legendre, F.; Poissonnet, S.; Bonnaillie, P.; Boulanger, L.; Forest, L. Microstructural Characterizations in Friction Stir Welded Oxide Dispersion Strengthened Ferritic Steel Alloy. J. Nucl. Mater. 2009, 386–388, 537–539. [Google Scholar] [CrossRef]
- Zhang, G.; Chandel, R.S.; Seow, H.P.; Hng, H.H. Microstructural Features of Solid State Diffusion Bonded Incoloy MA 956. Mater. Manuf. Process. 2003, 18, 599–608. [Google Scholar] [CrossRef]
- Zhang, H.; Senkara, J. Resistance Welding: Fundamentals and Applications, 2nd ed.; CRC/Taylor & Francis: Boca Raton, FL, USA, 2006; p. 53. ISBN 978-1-4398-5371-9. [Google Scholar]
- Corpace, F.; Monnier, A.; Poulon-Quintin, A.; Manaud, J.-P. Simulation of Resistance Upset Welding for ODS Steel Fuel Cladding. In Proceedings of the Conference Proceeding-JOM16/ICEW-7, Tisvildeleje, Denmark, 10–13 May 2011. [Google Scholar]
- Yazawa, Y.; Furuhara, T.; Maki, T. Effect of matrix recrystallization on morphology, crystallography and coarsening behavior of vanadium carbide in austenite. Acta Mater. 2004, 52, 3727–3736. [Google Scholar] [CrossRef]
- Yamamoto, M.; Ukai, S.; Hayashi, S.; Kaito, T.; Ohtsuka, S. Reverse Phase Transformation from α to γ in 9Cr-ODS Ferritic Steels. J. Nucl. Mater. 2011, 417, 237–240. [Google Scholar] [CrossRef]
Pieces to be welded: end plug and clad.
Schematic scenario of the resistance upset welding steps.
Schematic view of the welding device (Fw = welding force; Iw: welding current intensity; 1: end plug; 2: clad; 3: pneumatic jack; 4 and 5: electrodes).
Wavelength-dispersive spectroscopy (WDS) analysis of a welded zone with (Fw; Iw; tw; Cs) = (1800 N; 14 kA; 15 ms; 0.8 mm): (a) Back Scattering Electron (BSE) picture; (b) Corresponding yttrium distribution.
Evidence of the material deformation with the selected parameters (Fw; Iw; tw; Cs) = (2600 N; 14 kA; 10 ms; 0.8 mm).
Collapse value as a function of the dissipated energy for 32 experiments.
Example of a lack of joining (Mirror polish without etching) for a sample welded with the selected parameters (Fw; Iw; tw; Cs) = (2600 N; 14 kA; 10 ms; 0.8 mm).
Not welded length as a function of the dissipated energy for 32 experiments.
Evidence of modification of the metallurgical state of the sample welded using the parameters (Fw; Iw; tw; Cs) = (2600 N; 18 kA; 10 ms; 0.8 mm). (a) Optical micrograph of an etched sample; (b) WDS Yttrium distribution.
Yttrium modification (arbitrary unit defined in Table 3
) as a function of collapse value.
Range of the allowable dissipated energy to achieve welds with no lack of joining and no yttrium modifications (Cs = 0.2 mm).
WDS yttrium distribution for a weld within the working area with the selected parameters (Fw; Iw; tw; Cs) = (2400 N; 14 kA; 15 ms; 0.2 mm).
PM2000 nominal composition (wt %).
Process parameter range.
|Iw||Current intensity (kA)||14||18|
|tw||Welding time (ms)||10||15|
|Cs||Clad stick-out (mm)||0.2||0.8|
Classification used for the yttrium distribution modification.
|Arbitrary Unit||Shape and Extent|
|0||No yttrium modifications|
|1||Modification localised in the outer part of the joint with possible extension to the outer upset|
|2||Modification in the clad near the electrode piece contact|
|3||2 + spreading to the interface|
|4||3 + spreading through the interface to the inner upset|
© 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).