All-positional MMA electrodes with an acid rutile flux system on the alloyed core wire. Controlled Si and rare earth (RE) additions (mainly cerium) provide excellent oxidation resistance. Recovery is about 115% with respect to the core wire, and 65% with respect to the whole electrode.
Applications
Designed to match equivalent alloys with good hot strength coupled with excellent resistance to oxidation up to about 1100°C. Resistance to sulphidation under oxidising conditions is superior to many higher nickel heat-resistant alloys. Resistance to nitriding and carburisation is satisfactory except under reducing conditions where higher nickel alloys are superior. Also satisfactory for dissimilar combinations of materials with related levels of alloying. However, control of hot cracking in this high silicon weld metal is dependent on some ferrite being present during solidification. Caution is therefore required when considering dilution by dissimilar materials which could promote fully austenitic solidification, such as type 310 and other high nickel alloys. Combinations with alloys stabilised with Ti and especially Nb should be avoided, due to the possibility of embrittlement by Si-rich eutectics with these elements. Applications include furnaces and furnace parts, high-temperature flues, exhaust and heat recuperator systems, and combustion nozzles.