Nitrogen Dissolution Calculations During the GTA Welding of Steels

Research output: Contribution to conferencePaper

Abstract

The presence of nitrogen concentrations at levels much higher than Sieverts' Law predictions in iron and steel weldments is well established. Since there is no commonly accepted methodology to calculate this concentration, a computational methodology is developed to determine the nature and concentration of various species in the plasma phase above the weld pool surface. Based on this methodology, a comprehensive thermodynamic analysis of the plasma phase of a GTA welding arc containing nitrogen is performed. It shows that ionized species dominate close to the electrode, while neutral monatomic and diatomic nitrogen are the primary species near the metal surface. Furthermore, the equilibrium monatomic nitrogen partial pressure at even low plasma temperatures is high enough to cause nitrogen saturation in the weld metal. When oxygen is added to a nitrogen-containing plasma, the resulting nitrogen concentration in the weld metal is further enhanced. Definitive proof is provided here for a mechanism in which nitrogen and oxygen species interact in the plasma phase resulting in a significant increase in the concentration of monatomic nitrogen at plasma temperatures below 6000K. Emission spectroscopic analysis of glow discharge plasmas validates the presence of NO in nitrogen and oxygen containing plasmas.

Original languageEnglish (US)
Pages25-30
Number of pages6
StatePublished - Dec 1 1998
EventTrends in Welding Research: Proceedings of the 5th International Conference - Pine Mountain, GA, United States
Duration: Jun 1 1998Jun 5 1998

Other

OtherTrends in Welding Research: Proceedings of the 5th International Conference
CountryUnited States
CityPine Mountain, GA
Period6/1/986/5/98

Fingerprint

Steel
Dissolution
Welding
Nitrogen
Plasmas
Welds
Metals
Oxygen
Spectroscopic analysis
Electric arc welding
Glow discharges
Partial pressure
Iron
Thermodynamics
Temperature
Electrodes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanical Engineering

Cite this

Palmer, T., & Debroy, T. (1998). Nitrogen Dissolution Calculations During the GTA Welding of Steels. 25-30. Paper presented at Trends in Welding Research: Proceedings of the 5th International Conference, Pine Mountain, GA, United States.
Palmer, Todd ; Debroy, Tarasankar. / Nitrogen Dissolution Calculations During the GTA Welding of Steels. Paper presented at Trends in Welding Research: Proceedings of the 5th International Conference, Pine Mountain, GA, United States.6 p.
@conference{bd81d6b09b1b49c2b2f65f99e357a058,
title = "Nitrogen Dissolution Calculations During the GTA Welding of Steels",
abstract = "The presence of nitrogen concentrations at levels much higher than Sieverts' Law predictions in iron and steel weldments is well established. Since there is no commonly accepted methodology to calculate this concentration, a computational methodology is developed to determine the nature and concentration of various species in the plasma phase above the weld pool surface. Based on this methodology, a comprehensive thermodynamic analysis of the plasma phase of a GTA welding arc containing nitrogen is performed. It shows that ionized species dominate close to the electrode, while neutral monatomic and diatomic nitrogen are the primary species near the metal surface. Furthermore, the equilibrium monatomic nitrogen partial pressure at even low plasma temperatures is high enough to cause nitrogen saturation in the weld metal. When oxygen is added to a nitrogen-containing plasma, the resulting nitrogen concentration in the weld metal is further enhanced. Definitive proof is provided here for a mechanism in which nitrogen and oxygen species interact in the plasma phase resulting in a significant increase in the concentration of monatomic nitrogen at plasma temperatures below 6000K. Emission spectroscopic analysis of glow discharge plasmas validates the presence of NO in nitrogen and oxygen containing plasmas.",
author = "Todd Palmer and Tarasankar Debroy",
year = "1998",
month = "12",
day = "1",
language = "English (US)",
pages = "25--30",
note = "Trends in Welding Research: Proceedings of the 5th International Conference ; Conference date: 01-06-1998 Through 05-06-1998",

}

Palmer, T & Debroy, T 1998, 'Nitrogen Dissolution Calculations During the GTA Welding of Steels' Paper presented at Trends in Welding Research: Proceedings of the 5th International Conference, Pine Mountain, GA, United States, 6/1/98 - 6/5/98, pp. 25-30.

Nitrogen Dissolution Calculations During the GTA Welding of Steels. / Palmer, Todd; Debroy, Tarasankar.

1998. 25-30 Paper presented at Trends in Welding Research: Proceedings of the 5th International Conference, Pine Mountain, GA, United States.

Research output: Contribution to conferencePaper

TY - CONF

T1 - Nitrogen Dissolution Calculations During the GTA Welding of Steels

AU - Palmer, Todd

AU - Debroy, Tarasankar

PY - 1998/12/1

Y1 - 1998/12/1

N2 - The presence of nitrogen concentrations at levels much higher than Sieverts' Law predictions in iron and steel weldments is well established. Since there is no commonly accepted methodology to calculate this concentration, a computational methodology is developed to determine the nature and concentration of various species in the plasma phase above the weld pool surface. Based on this methodology, a comprehensive thermodynamic analysis of the plasma phase of a GTA welding arc containing nitrogen is performed. It shows that ionized species dominate close to the electrode, while neutral monatomic and diatomic nitrogen are the primary species near the metal surface. Furthermore, the equilibrium monatomic nitrogen partial pressure at even low plasma temperatures is high enough to cause nitrogen saturation in the weld metal. When oxygen is added to a nitrogen-containing plasma, the resulting nitrogen concentration in the weld metal is further enhanced. Definitive proof is provided here for a mechanism in which nitrogen and oxygen species interact in the plasma phase resulting in a significant increase in the concentration of monatomic nitrogen at plasma temperatures below 6000K. Emission spectroscopic analysis of glow discharge plasmas validates the presence of NO in nitrogen and oxygen containing plasmas.

AB - The presence of nitrogen concentrations at levels much higher than Sieverts' Law predictions in iron and steel weldments is well established. Since there is no commonly accepted methodology to calculate this concentration, a computational methodology is developed to determine the nature and concentration of various species in the plasma phase above the weld pool surface. Based on this methodology, a comprehensive thermodynamic analysis of the plasma phase of a GTA welding arc containing nitrogen is performed. It shows that ionized species dominate close to the electrode, while neutral monatomic and diatomic nitrogen are the primary species near the metal surface. Furthermore, the equilibrium monatomic nitrogen partial pressure at even low plasma temperatures is high enough to cause nitrogen saturation in the weld metal. When oxygen is added to a nitrogen-containing plasma, the resulting nitrogen concentration in the weld metal is further enhanced. Definitive proof is provided here for a mechanism in which nitrogen and oxygen species interact in the plasma phase resulting in a significant increase in the concentration of monatomic nitrogen at plasma temperatures below 6000K. Emission spectroscopic analysis of glow discharge plasmas validates the presence of NO in nitrogen and oxygen containing plasmas.

UR - http://www.scopus.com/inward/record.url?scp=1442355999&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1442355999&partnerID=8YFLogxK

M3 - Paper

SP - 25

EP - 30

ER -

Palmer T, Debroy T. Nitrogen Dissolution Calculations During the GTA Welding of Steels. 1998. Paper presented at Trends in Welding Research: Proceedings of the 5th International Conference, Pine Mountain, GA, United States.