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3723769 
Journal Article 
Flux-Coating Development for SMAW Consumable Electrode of High-Nickel Alloys Extrudability, recovery analysis, and welding characteristics were incorporated into a shielded metal arc welding electrode for welding high-nickel alloys 
Sham, K; Liu, S 
2014 
1 
Welding Journal
ISSN: 0043-2296 
93 
8 
271S-281S 
WOS:000346330100010 
There is interest in improved high-nickel alloy electrodes for shielded metal arc welding (SMAW) to replace gas tungsten arc welding (GTAW) with cold wire feed for pressure vessel fabrication/repair in the power-generation industry. Without altering the GTAW wire composition, a proper flux coating was designed to produce a SMAW electrode to give an enhanced weld composition. SMAW electrodes were designed by developing proper flux coatings for extrusion, welding characteristics, and weld integrity. The flux formulation design began with an equal distribution of three primary ingredients: cryolite, rutile, and calcium carbonate to clean the weld, create a slag, and provide shielding gas, respectively. The system was then optimized to enhance extrudability, slag detachability, electrode weldability, alloying recovery, arc stability, and a number of weld properties. Detailed mass balance calculations were performed to determine alloying element transfer across the arc and to understand weld metal recovery from the flux coating, filler metal wire, and base metal. For chromium and manganese, an average of 95 and 60% weld recovery was confirmed and determined, respectively. The elemental recovery data determined were important for calculating the proper additions of these elements into the flux formulation. Comparisons revealed comparable welding characteristics for the in-house manufactured and commercial SMAW electrodes. Arc voltage analysis was also performed to determine arc stability of these electrodes. Results indicated differences in metal transfer modes between the different flux coating iterations, and the final electrodes exhibited more consistent voltage-time traces. This work demonstrates that even though it is common practice to use a GTAW wire to build a SMAW electrode, the flux coating can be designed to beneficially alter the weld composition. 
Covered Electrode; SMAW Consumable; Nickel Alloys; Flux Coating; Extrusion; Electrode Manufacture; Composition