Abstract: The present invention provides a process for maintaining magnesium-containing cast iron melts in a castable state for comparatively long periods of time of, for example, several hours or days, with the use of a protective gas atmosphere, wherein the protective gas atmosphere present above the surface of the melt, as well as all the adjacent parts of the apparatus used, is kept at a temperature above the boiling point of magnesium, i.e. 1102.degree. C., and always has a partial pressure of magnesium vapor which is the same as or greater than the vapor pressure of the magnesium within the melt.