Stainless-steel-sheathed and inconel-sheathed cables with the outer diamete of 1.0mmφ were welded to nipples of stainless steel or inconel by two methods with an electron-beam and a microplasma-arc. The performance of the welds was examined through electrical insulation, autoclave, tensile and bending tests as well as metallographical examinations.
The electrical insulation and autoclave tests showed that the welded parts by both methods have the capability of excellent sealing in a high-temperature and high-pressure water environment such as in the in-core of LWR. The metallographical examinations, however, showed that the grain growth and structure change in the vicinity of the welded part were comparatively marked in the case of micro-plasma-arc welding. The tensile strengths were about 20-30kg in both cases, and the bending strength, i.e. the repetition number of bending between +45° and -45°, exceeded 40 times until the cable broke. The welds are considered to have strengths enough for actual applications.
Also, it was shown that the above tests and examinations were very effective to find out the faulty weld.
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