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

摘要

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 embrittlement besides the well-known low-temperature 475 deg C embrittlement. The high-temperature embrittlement is provoked by submicroscopic precipitates but can be remedied by a special annealing treatment. The results with enhanced ductility of the ferritic microstructure are confirmed under manufacturing conditions for semifinished products such as slabs, billets, bars, wire rod and strips, depending on alloying contents of mainly chromium and aluminium. In the field of near-net-shape casting, first results also confirm the same beneficial effect. Using the heat-content of the casting and rolling for the annealing process, moreover, results in lower process costs.