The effects of liquid aluminium on hot-work tool steel H13 have been studied using specimens in three different surface conditions: rough, polished and oxidized. The specimens were rotated around their own axes in molten aluminium at different temperatures and for different exposure times. Three intermetallic phases of Fe-Al which formed on the surface of the steel when submerged in liquid aluminium were identified. These were shown to grow as continuous layers or as cone-shaped dendrites, depending on the surface condition of the steel. The growth of these layers/cones was related to time and temperature. The formation of cones and their subsequent breaking is assumed to be an important factor in the erosion of die-casting dies.
