First results of process-studies to enhance the ductility of ferritic steels containing chromium mass contents of more than 8%

Otherwise their drawback is the tendency towards cold brittleness expressed by their low impact energy values. They obtain the high range of ductility only at temperatures higher than room temperature. It was found that this low ductility at room temperature is caused by a high-temperature embrittle ment besides the well-known low-temperature 475 degrees C embrittlement. Th e high-temperature embrittlement is provoked by submicroscopic precipitates but can be remedied by a special annealing treatment. The results with enh anced ductility of the ferritic microstructure are confirmed under manufact uring conditions for semifinished products such as slabs, billets, bars, wi re rod and strips, depending on alloying contents of mainly chromium and al uminium. In the field of near-net-shape casting, first results also confirm the same beneficial effect. Using the heat-content of the casting and roll ing for the annealing process, moreover, results in lower process costs.