The RRR Parameter of the ITER Type Bronze-Route Cr-Coated Nb$_{3}$Sn Strands After Different Heat Treatments

Abdyukhanov, I. M.; Vorobieva, A.; Dergunova, E. A.; Polikarpova, M.; Mareev, K. A.; Traktirnikova, N. V.; Novosilova, D. S.; Pantsyrny, V.; Lukyanov, Pavel

doi:10.1109/tasc.2011.2180281

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…The 8 TF strand types are covering several different heat treatment cycles with different durations and temperature plateaux. This has to be considered if comparing the quality or RRR performance [20][21][22]. Furthermore, batch variations are more pronounced in case of multiple suppliers for the Cu stabiliser.…”

Section: Residual Resistance Ratio (Rrr) and Cr Platingmentioning

confidence: 99%

Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils

Vostner¹,

Jewell

Pong

et al. 2017

Supercond. Sci. Technol.

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The ITER toroidal field (TF) strand procurement initiated the largest Nb 3 Sn superconducting strand production hitherto. The industrial-scale production started in Japan in 2008 and finished in summer 2015. Six ITER partners (so-called Domestic Agencies, or DAs) are in charge of the procurement and involved eight different strand suppliers all over the world, of which four are using the bronze route (BR) process and four the internal-tin (IT) process. In total more than 500 tons have been produced including excess material covering losses during the conductor manufacturing process, in particular the cabling. The procurement is based on a functional specification where the main strand requirements like critical current, hysteresis losses, Cu ratio and residual resistance ratio are specified but not the strand production process or layout. This paper presents the analysis on the data acquired during the quality control (QC) process that was carried out to ensure the same conductor performance requirements are met by the different strand suppliers regardless of strand design. The strand QC is based on 100% billet testing and on applying statistical process control (SPC) limits. Throughout the production, samples adjacent to the strand pieces tested by the suppliers are cross-checked ('verified') by their respective DAs reference labs. The level of verification was lowered from 100% at the beginning of the procurement progressively to approximately 25% during the final phase of production. Based on the complete dataset of the TF strand production, an analysis of the SPC limits of the critical strand parameters is made and the related process capability indices are calculated. In view of the large-scale production and costs, key manufacturing parameters such as billet yield, number of breakages and piece-length distribution are also discussed. The results are compared among all the strand suppliers, focusing on the difference between BR and IT processes. Following the completion of the largest Nb 3 Sn strand production, our experience gained from monitoring the execution of the QC activities and from auditing the results from the measurements is summarised for future superconducting strand material procurement activities.

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Section: Residual Resistance Ratio (Rrr) and Cr Platingmentioning

confidence: 99%

Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils

Vostner¹,

Jewell

Pong

et al. 2017

Supercond. Sci. Technol.

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“…It has been suggested that during the initial stages of HT the increase of RRR values is associated with the decrease of structural defects [14], while at higher HT temperatures the precipitation and redissolution of impurities would account for an increase in resistivity [15]. Table I.…”

Section: Ofhc Coppermentioning

confidence: 99%

Bulge testing of copper and niobium tubes for hydroformed RF cavities

Kim

Sumption

Susner

et al. 2016

Materials Science and Engineering: A

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The heat treatment, tensile testing, and bulge testing of Cu and Nb tubes has been carried out to gain experience for the subsequent hydroforming of Nb tube into seamless superconducting radio frequency (SRF) cavities for high energy particle acceleration. In the experimental part of the study samples removed from representative tubes were prepared for heat treatment, tensile testing, residual resistance ratio measurement, and orientation imaging electron microscopy (OIM). After being optimally heat treated Cu and Nb tubes were subjected to hydraulic bulge testing and the results analyzed. In the final part of the study finite-element models (FEM) incorporating constitutive (stress-strain) relationships analytically derived from the tensile and bulge tests, respectively, were used to replicate the bulge test. As expected, agreement was obtained between the experimental bulge parameters and the FEM model based on the bulge-derived constitutive relationship. Not so for the FEM model based on tensile-test data. It is concluded that a constitutive relationship based on bulge testing is necessary to predict a material's performance under hydraulic deformation.

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The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

2014

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The RRR Parameter of the ITER Type Bronze-Route Cr-Coated Nb$_{3}$Sn Strands After Different Heat Treatments

Cited by 7 publications

References 4 publications

Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils

Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils

Bulge testing of copper and niobium tubes for hydroformed RF cavities

The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

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The RRR Parameter of the ITER Type Bronze-Route Cr-Coated Nb$_{3}$Sn Strands After Different Heat Treatments

Cited by 7 publications

References 4 publications

Statistical analysis of the Nb3Sn strand production for the ITER toroidal field coils

Statistical analysis of the Nb3Sn strand production for the ITER toroidal field coils

Bulge testing of copper and niobium tubes for hydroformed RF cavities

The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

Contact Info

Product

Resources

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Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils

Statistical analysis of the Nb₃Sn strand production for the ITER toroidal field coils