Vliv elektrolytického vodíkování na zkřehnutí duplexních ocelí

Abstract

The thesis is aimed at hydrogen embrittlement of ferritic-austenitic duplex steel 22/05. The resistance of duplex steel to hydrogen damage at speed load v = 0,5 mm/min was determined by tensile testing on samples with diameter d0 = 4 mm and length L0 = 20 mm. Hydrogen saturation of samples was done by electrolytic in 0,1N solution of H2SO4 with addition of 1 g of KSCN per liter of solution for 24 hours. The material in initial state was also heat treated at 700°C for 5 hours and then cooled by air, with the aim of causing precipitation of the sigma phase and material embrittlement. Volume fraction of the sigma phase was determined by image analysis. The samples were then again hydrogen electrolytic saturation under the same conditions as the material in initial state. The aim of the work was to observe influence of hydrogen on the change of mechanical properties of duplex steel and character of fracture surfaces of hydrogen electrolytic saturated samples and the calculation of index of hygrogen embrittlement F. The thesis partly follows on my bachelor thesis.