Deuterium retention in the material of welded seam rafm steel EK-181 (Rusfer)

For the first time, deuterium retention in the welded seam of the domestic reduced-activation ferritic-martensitic (RAFM) steel EK-181 (Rusfer) was investigated in comparison with the usual samples of the same steel. The welded seam was obtained by the argon arc welding method of two sheets of steel EK-18 with a thickness of 2 mm. Samples were kept in gaseous deuterium at a pressure of 5 atmospheres and temperatures in the range of 623–773 K for 25 hours. The number of retained deuterium was determined by thermal desorption spectrometry (TDS). It was found that after exposure in the gas, samples carved from a weld retained about 2 times more deuterium than samples from conventional steel EK-181. The number of peaks in TDS spectra is the same for both ordinary steel and the area of the weld. The TDS spectra modeling was carried out using the TMAP7 code. The proposed model includes the presence of oxides on the surface and a high concentration of defects in the surface layer of samples, wherein well describing the experimental TDS spectra. The possible nature of hydrogen states in steel is discussed, which determines the features of TDS spectra.