LMFBR steam generator tube-to-tubesheet weld with dissimilar ferritic steels - qualification tests and inelastic analyses

To weld steam-generating tubes of EM12 to a tubesheet provided with boss of 2.25 Cr. 1 Mo, STEIN INDUSTRIE has developed a process of internal welding without filler metal. The characterization tests carried out on test assemblies have shown the excellent metallurgical quality of welding performed by this process. High-temperature strength tests showed a safety margin as compared with the results of the finite element calculations. The hypotheses made for these calculations which take into account the elastoviscoplatic properties of materials, and particularly the extension of the properties of 2.25 Cr. 1 Mo to the weld, can therefore be applied to steam-generator sizing calutations. (orig.)