Work

Effect of flux composition on metal transfer characteristics in rutile-type flux-cored arc welding

Year: 2026

Type: article

Abstract: This study clarified the effects of flux composition on metal transfer characteristics in rutile-type Flux-Cored Arc Welding (FCAW). Seven prototype wires with varying TiO 2 , SiO 2 , and CaF 2 contents in the flux were tested at three currents (220–280 A) under Ar-20%CO 2 shielding. The Droplet Diameter (DD), which is important for arc stability, is proportional to the ratio of the Wire Feed Speed (WFS) and the Metal Transfer Frequency (MTF), which are primarily governed by the energy and force balances, respectively. The WFS depended on the iron content in the flux, was almost independent of the TiO 2 , SiO 2 , and CaF 2 content, and increased linearly with current. Increasing the CaF 2 content reduced the MTF sharply from 86.9 to 34.0 Hz at 220 A due to either the strong recoil pressure caused by vaporization from CaF 2 or strong arc pressure by the high specific heat of CaF 2 plasma. These pressures pushed the droplet upward, hindering droplet detachment. TiO 2 showed a slight increase in MTF with TiO 2 content (for example, 162.5 to 170.3 Hz at 280 A). SiO 2 showed a significant increase in MTF with SiO 2 content, especially at 280 A (170.3 to 222.9 Hz), probably due to slag-metal reactions increasing the oxygen concentration in the droplets, leading to a lower surface tension; the effect is stronger for SiO 2 because its basicity lower than that of TiO 2 . Thus, the flux composition affected the MTF much more strongly than the WFS, so that the DD was inversely proportional to MTF. Consequently, it was found that the DD depended strongly on flux composition through variations in the physical properties.

Source: The International Journal of Advanced Manufacturing Technology

DOI: 10.1007/s00170-026-17867-3