Electrochemical effects on weld pool chemistry in submerged arc and dc electroslag welding
Electrochemical reactions could be an important factor governing the chemistry of weld pools in dc welding. The anodic reaction at the weld wire-slag interface leads to a relatively high Po/sub 2/ which leads to the formation of an oxide nO/sup 2 -/ + M(metal) ..-->.. MO/sub n/ + 2ne where M is a metal at the weld wire-slag interface and n is related to the valence of M in the oxide. After the molten weld wire forms a droplet which separates from the wire, the electrochemical reaction ceases and the oxide dissolves in the flux. The cathodic reactions at the weld pool lead to the electrodeposition of metals M/sup 2 +/(slag) + 2e ..-->.. M(metal); Si/sup 4 +/(slag) + 4e ..-->.. Si(metal) where M can be Fe/sup 2 +/, Mn/sup 2 +/. or other metals which are electrodeposited at the interface. The relative amounts of all these deposits wil be readjusted by chemical reactions such as Si(metal) + 2MO(slag) ..-->.. SiO/sub 2/(slag) + 2M(metal); Mn(metal) + FeO(slag) ..-->.. MnO(slag) + Fe(metal). The resultant changes in the compositions of the weld metal and the slag depend on the rates of the electrodeposition reactions relative to the rates of the back reactions. If the proposed mechanism is correct, experimental data would indicate that both the electrochemical and back reactions appear to be important. Analogous electrochemical reactions can occur at metal-plasma interfaces.
- Research Organization:
- Argonne National Lab., IL (USA); Colorado School of Mines, Golden (USA). Dept. of Metallurgial Engineering
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 5542939
- Report Number(s):
- CONF-860594-6; ON: DE86012117
- Resource Relation:
- Conference: ASM international trends in welding research meeting, Gatlinburg, TN, USA, 18 May 1986; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Gas/metal/slag reactions in submerged arc welding using CaO-Al/sub 2/O/sub 3/ based fluxes
Submerged arc flux welding with CaF/sub 2/-CaO-SiO/sub 2/ fluxes: Possible electrochemical effects on weld metal