J Mater Sci Technol ›› 2003, Vol. 19 ›› Issue (Supl.): 225-227.

• Research Articles • Previous Articles     Next Articles

Research on the Mechanism of Penetration Increase by Flux in A-TIG Welding

Chunli YANG, Sanbao LIN, Fengyao LIU, Lin WU, Qingtao ZHANG   

  1. State Key Lab. of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2003-12-28 Published:2009-10-10
  • Contact: Chunli YANG

Abstract: The mechanism of penetration depth increased by activating flux in activating tungsten inert gas (A-TIG) welding was studied by measuring the distribution of trace element Bi in the weld and monitoring the change of arc voltage during A-TIG welding of stainless steel 0Cr18Ni9 with fluxes SiO2 and TiO2. The results show that the mechanism of penetration depth in A-TIG welding depends on the sort of flux used. The weld pool convection after coating the flux SiO2 and flux TiO2 is changed inversely compared with convectional TIG welding without flux. The arc voltage is increased by flux SiO2 whilst flux TiO2 does not have effect on the arc voltage. The reason of penetration depth increase for SiO2 is due to the constriction of arc plasma and the change of surface tension gradient. The increase of weld penetration depth with TiO2 only ascribes to the change of surface tension gradient.

Key words: TIG welding, Activating flux, Surface tension, Arc voltage