Study of the effect of hydrogen content on the mechanical properties in press-hardened boron steel

In this master thesis the mechanical aspects of hydrogen embrittlement such as hydrogen content, strength, fracture mode and microstructural changes were studied in press-hardened boron steel. The specimens were charged electrochemically in a 5% H2SO4 + 30 mg/l As2O3 solution. By using different current densities and charging times various hydrogen content were obtained. The hydrogen charged specimens were then subjected to a low strain rate tensile test in order to investigate the effect of hydrogen on the mechanical properties. With increasing hydrogen content a reduced ductility as well as strength could be observed. Fractography was carried out using Scanning Electron Microscopy (SEM) and light microscopy. Hydrogen assistant fractures were found to be both intergranular brittle and transgranular ductile.Validerat; 20101217 (root)