| Autor: |
Singer, W., Singer, X., Tiessen, J., Wen, H. M., Schölz, F. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2003, Vol. 671 Issue 1, p162, 14p |
| Abstrakt: |
Experiences concerning RRR degradation and gas absorption of high purity niobium welded at different electron beam (EB) facilities are summarized. The oxygen and nitrogen content is increased as a rule at the welding seam. The absorption of hydrogen takes place not directly at the welding seam but in the heat-affected area. The RRR degradation is moderate, if the total pressure is better than 5×10[SUP-5] mbar and the preparation is done under clean condition. A series of welding was done in the new DESY EB facility, which was specifically designed to meet the requirements for the welding of niobium cavities for TESLA. High vacuum (between 2×10[SUP-8] and 2×10[SUP-6] mbar) allowed improving the niobium purity at the welding seam, in which the RRR were increased from 350 to ca. 370-380. The distribution of RRR, gases, grain size and thermal conductivity in the welding area are analyzed. The repair of a burned hole in the cavity is also discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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