Studium chování CrMo oceli pro výrobu ocelových bezešvých vysokotlakých lahví v prostředí vodíku

Abstract

The theoretical part of the thesis is focused on the description and characteristics of the most commonly used CrMo steels for the production of cylinders. The chemical composition of these steels is described, specifically the influence of alloying elements on their microstructure and mechanical properties. Much attention is focused on the issue of hydrogen embrittlement and hydrogen traps in steels. In the experimental part of the work, the change of mechanical properties of 34CrMo4 steel in hydrogen environment and its relation to microstructure is investigated. The test samples of the investigated material were electrolytically hydrogenated for 8 h at different current densities in H2SO4 solution with the addition of 1 g of KSCN and then tested by SSRT method. This method consists of deforming the sample at a slow rate. The degree of hydrogen embrittlement was expressed by the hydrogen embrittlement index. Finally, fractographic analysis of the ruptured test samples was performed using a scanning electron microscope. The morphology of the fracture surface was studied for both the samples in their original state (without hydrogenation) and for the samples after hydrogenation.