Welding Journal Research Supplement

Abstract

Droplet temperatures in metal-cored arc welding (MCAW) were measured for the first time using a solid-state calorimeter and a water-cooled cathode, with a commercial metal-cored wire and pure argon shielding gas, and a current range of 210 to 290 A. In MCAW, droplet temperatures ranged from 1900°C to 2145°C with an average uncertainty of ± 35.5°C. Compared to gas metal arc welding (GMAW) at the same current range, droplet temperatures in MCAW were consistently lower than those in GMAW, with an average difference of approximately 260°C. High-speed video revealed that the metal core, consisting mostly of iron powder in the MCAW, remained in a near-solid state until immediately before detachment, contributing to lower droplet temperatures. A mass and energy balance analysis indicated that the sheath was hotter than droplet temperature by approximately 150°C and 90°C at the assumed core temperatures of 1200°C and 1500°C, respectively. The molten sheath temperature was predicted to be comparable to that of solid wire in GMAW under similar conditions. In MCAW, the metal transfer mode remained globular, while the transfer morphology shifted from symmetrical to biased droplet formations with rising current. MCAW also exhibited higher overall anode fall voltages (7.9-10.0 V) compared to GMAW (6.8 V), which was attributed to either the Thomson effect near the electrode or changes in metal transfer morphology. The presence of a colder powder core suggests a reduction in manganese evaporation, which could significantly lower manganese https://doi.org/10.29391/2026.105.014 fume emissions, an important consideration for occupational health and environmental safety.