In present work, two nuclear grade steel (P91, P92) are joined using the arc welding process. The welded joints were subjected to the heat treatment in order to restore the mechanical properties and overcome the heterogeneity across the joints. The weldments were studied for microstructure evolution and mechanical behavior under different condition of heat treatment. The variation in mechanical behavior obtained for the welded joints were tried to relate the microstructural evolution. After the normalizing based heat treatment, homogeneity with negligible δ ferrite across the welded joints was observed.
The succesive fifth whole-year research expedition stayed at the polar station of the Institute of Geophysics, Polish Academy of Sciences, in the Hornsund fiord from July 1982 to August 1973. Continuous observations as well as sejsmologic, magnetic and meteorological records, constituting continuation of the investigations started in summer 1978. were carried out by the wintering group of 8 men. Also separate research programmes: physics of atmosphere and ionosphere, sedimcntologo-oceanological, geomorphological and medical investigations, including observations of white bears, were realized. Many technical works, repairs and adaptations were carried out as well.