[en] Within the framework of our studies to find out suitable materials for HLW canisters serving as a barrier in a salt repository the corrosion behaviour was investigated of a selected mild steel. The investigations (immersion tests) were made under selecting conditions in two brines of greatly differing MgCl²-concentrations (Q-brine: 26.8 wt.% MgCl² at 55₀C and MgCl²-rich solution: 45 wt.% at 170₀C) at temperatures ranging from 35₀C to 170₀C. To facilitate the interpretation of the results, soft iron was included in the investigations and likewise distilled water as a corrosion medium. The investigations revealed a greatly differing influence of temperature on the corrosion of the materials in the Q-brine and in distilled water. The materials under investigation showed a similar corrosion behaviour in qualitative terms in all corrosion media and at all temperatures. In addition to a uniform corrosion, zones showing shallow pits were found by metallographic means whose maximum penetration depth was frequently much higher than the mean uniform corrosion rate. The conclusion can be drawn from the results obtained so far that HLW containers of fine grain mild steel can take over a barrier function in the repository for an extended period of time provided the wall thickness is dimensioned appropriately. (orig./IHOE)