The effect of altitude on welding
- Colorado School of Mines, Golden, CO (United States)
Welding at high altitude has typically been reported as more difficult, particularly in the aspect of porosity control. As a consequence, welding of a similar assembly in cities of high elevation such as Denver, Colorado (USA) and Mexico City (Mexico) may require different parameters from those selected for welding in Houston, Texas (USA), Kobe (Japan), and Hamburg (Germany). The atmospheric pressures in these locations are different and the solubilities of bases such as hydrogen in the weld metal are also expected to be different. In this work, the formation of hydrogen and carbon monoxide porosity in low carbon steel weld metals was investigated. The thermodynamic conditions of the chemical reactions that occur in the weld poor were examined. The effects of ambient pressure on the H-O and C-O reactions were estimated for a range of pressures that varied from sea level to approximately 10,000 feet elevation. It was determined that the amounts of carbon monoxide and water in the pores varied measurably with altitude. Since the water vapor molecules that are entrapped in a pore react favorably with the iron atoms on the surface of the pore to form hydrogen and iron oxide, the amount of retained carbon monoxide and hydrogen would also vary with altitude. Finally, welds performed at lower ambient pressure (in locations of higher elevation) are expected to exhibit a larger amount of porosity because of reaction thermodynamics and nucleation kinetics.
- Sponsoring Organization:
- Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 442957
- Report Number(s):
- CONF-950682-; ISBN 0-87170-567-2; TRN: IM9712%%382
- Resource Relation:
- Conference: 4. international conference on trends in welding research, Gatlinburg, TN (United States), 5-9 Jun 1995; Other Information: PBD: 1996; Related Information: Is Part Of Trends in welding research: Proceedings of the 4. international conference; Smartt, H.B.; Johnson, J.A. [eds.] [Idaho National Engineering Lab., Idaho Falls, ID (United States)]; David, S.A. [ed.] [Oak Ridge National Lab., TN (United States)]; PB: 836 p.
- Country of Publication:
- United States
- Language:
- English
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