Category: Uncategorized

Alloying is the introduction of alloy components into a molten mass, in order to produce an alloy or to correct or adjust an existing alloy.

Alitisation is a surface protection process for steel and certain types of iron for the improvement of the scaling resistance by means of the infusion of aluminium. The aluminium is applied by means of spraying or immersion, and then diffuses into the material by annealing. Material treated in this way becomes resistant to scaling up to approx. 950 °C.

For safety reasons, the melting bath in a crucible induction furnace should be continually earthed. This earthing is as a rule provided by bottom electrodes. In the case of ceramically lined furnaces, this is no problem. When using crucibles of graphite clay or silicon carbide, a spiral of the heat-resistant steel 1.4828 (X15CrNiSi20-12) is embedded in graphite beneath the crucible and connected to earth potential outside the furnace housing.

Another method is earthing by means of the casting spout, in which is a shackle which is welded on one side to the steel construction. With the 1st casting from a crucible, the molten metal flows over the shackle, and the bath is then earthed via the conducting crucible. Lost tamping forms have as a rule no connection with the bottom electrodes during the sintering charge, since the crucible bottom is tamped 5- 10 mm higher than the bottom electrodes. In order to ensure earthing in this case, the earthing between the form and earth can be created with the aid of an earth cable with 2 contact magnets, in the same way as for arc welding.