Mass transfer of the nickel-base alloy covered electrode with neutral flux coating during shielded metal arc welding

• Published in: International journal of heat and mass transfer 2014-11, Vol.78, p.1095-1104
• Main Authors: Qin, Renyao, He, Guo
• Format: Article
• Language: English
• Subjects: Chromium; Coating; Coefficients; Covering; Electrodes; Flux; Manganese; Mass transfer; Mass transfer coefficient; Neutral type covered electrode; Nickel-base alloy; Shielded metal arc welding
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2014.07.074

The mass transfer of the nickel-base alloy covered electrodes with the near neutral CaO–CaF2–TiO2 type flux coating (accorded with AWS ENiCrFe-7) during shielded metal arc welding has been investigated by directly measuring their deposited metal compositions. The results indicate that the Nb mass transfer coefficient is in the range of 46–61pct; Mn in the range of 51–66pct; Cr in the range of 80–89pct; and Fe in the range of 82–92pct. The weight coefficient of the flux coating, the particle size of the metal powders and the flux ingredients together affect the mass transfer. As the particle size increases, the Mn and Cr mass transfer coefficients increase. As the weight coefficient of the coating increases, the metal mass transfer coefficients decrease. The deoxidizers in the flux coating can improve the metal mass transfer. Fe3O4 in the flux coating reduces the Nb and Fe mass transfer coefficients, but increases the Mn mass transfer coefficient. The metal contents in the flux coating also affect the metal mass transfer. Compared with the typical basic and acidic covered electrodes, the nickel-base alloy covered electrodes with the near neutral CaO–CaF2–TiO2 type flux coating exhibit moderate metal mass transfer coefficients. The highest mass transfer coefficients of Mn, Cr and Fe appear in the basic CaO–CaF2 type covered electrodes, but the highest Nb mass transfer coefficient has been found in the acidic CaO–TiO2–SiO2 type covered electrodes.