KARAKTERISTIKE PONAŠANJA NAJNOVIJE GENERACIJE HROM MOLIBDEN ČELIKA GRUPE SA 387 Gr. 91 PRI OBLIKOVANJU PROIZVODA POSTUPCIMA ZAVARIVANJA I ODRŽIVI RAZVOJ / CHARACTERISTICS OF THE BEHAVIOR OF THE LATEST GENERATION CHROMIUM MOLYBDENUM STEEL GROUP SA 387 Gr. 91 IN PRODUCT SHAPING BY WELDING PROCESSES AND SUSTAINABLE DEVELOPMENT

Abstract

Chromium-molybdenum steel group SA 387 Gr. 91 is the latest from the generation of steels designed to operate under high temperature, elevated pressure, and corrosive environments. The most important characteristics of this steel, compared to previously used steels for high-temperature applications, are its high yield strength, good corrosion resistance, significant oxidation resistance, and excellent creep resistance. The latter property enables engineers to design components with significantly thinner walls compared to other types of steels (material savings). In addition to its good mechanical properties at elevated temperatures, weldability is also important for this steel and, in general, for the entire group of such steels. It is crucial that welding does not affect their resistance to corrosion, creep, or their overall mechanical properties, thus extending the remaining lifespan of the structure, which, together with material savings, fits into the concept of sustainable development. This paper will present the characteristics of the behavior of Cr-Mo steels during welding, based on experimental testing (macro and microstructural examination of the welded joint, technological tests – bend testing, hardness testing).