Heavy-duty plasma-arc powder surfacing with duplex steels

摘要

The coating of structural steels with duplex materials by heavy-duty plasma-arc powder surfacing promises lower levels of dilution than with conventional surfacing and hence good corrosion resistance. Therefore surfacing experiments took place with the duplex steel X2CrNiMoN25-7-4 as coating material. For the heavy-duty torch, a plasma-arc powder nozzle was developed and the processing parameters were optimised with regard to heat input and flux delivery. The corrosion qualities were examined by measuring the current density potential curves and the critical pitting corrosion temperature and evaluating the intercrystalline corrosion. It turned out, that extensive coatings can be produced in one layer with dilution levels under 10% economically.