Effect of shielding gas on the properties and microstructure of melted steel surface using a TIG torch

P. Munoz-Escalona, S. Mridha, T. N. Baker

Research output: Contribution to journalArticle

Abstract

A surface engineering technique based on a tungsten inert gas (TIG) torch was used to melt single tracks on the surface of a microalloyed steel with a hardness of 150 HV. The influence of three shielding gases, argon, helium and nitrogen, on the microstructure and hardness of the re-solidified surfaces was analysed. In all melting techniques, the heat generated by the source is normally conducted to the substrate ahead of the torch and has been described as 'preheat'. This leads to a gradually higher substrate temperature, from the start to the finish of a melted surface track. The aim of this research was to analyse any inhomogeneities in the microstructure, due to 'preheat', which is rarely considered in the published literature. Three thermocouples were located along the melted track in order to record the temperature at three different points. An energy input of ~840 J/mm was used in each experiment, and the results show that the maximum temperature recorded by the last thermocouple, No three (subjected to the preheat), for argon, helium and nitrogen gas was 590, 1120 and 740 °C, respectively, where a difference of 150 and 200 °C was registered between the first and third thermocouples when using helium and nitrogen, respectively. The corresponding hardness values were 170, 162 and 225 HV, and the corresponding surface roughness values were 6, 12 and 25 ?m. A decrease by almost 60% in the roughness value was observed between the initial and last stage of the melted track, when using argon as shielding gas.
Original languageEnglish
Pages (from-to)435-443
Number of pages9
JournalAdvances in Materials and Processing Technologies
Volume1
Issue number3-4
DOIs
Publication statusPublished - 28 Jan 2016

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torches
shielding
rare gases
tungsten
thermocouples
steels
microstructure
hardness
helium
argon
gases
nitrogen
temperature
surface roughness
inhomogeneity
roughness
melting
engineering
heat
energy

Keywords

  • surface engineering
  • shielding gas
  • TIG
  • surface roughness

Cite this

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abstract = "A surface engineering technique based on a tungsten inert gas (TIG) torch was used to melt single tracks on the surface of a microalloyed steel with a hardness of 150 HV. The influence of three shielding gases, argon, helium and nitrogen, on the microstructure and hardness of the re-solidified surfaces was analysed. In all melting techniques, the heat generated by the source is normally conducted to the substrate ahead of the torch and has been described as 'preheat'. This leads to a gradually higher substrate temperature, from the start to the finish of a melted surface track. The aim of this research was to analyse any inhomogeneities in the microstructure, due to 'preheat', which is rarely considered in the published literature. Three thermocouples were located along the melted track in order to record the temperature at three different points. An energy input of ~840 J/mm was used in each experiment, and the results show that the maximum temperature recorded by the last thermocouple, No three (subjected to the preheat), for argon, helium and nitrogen gas was 590, 1120 and 740 °C, respectively, where a difference of 150 and 200 °C was registered between the first and third thermocouples when using helium and nitrogen, respectively. The corresponding hardness values were 170, 162 and 225 HV, and the corresponding surface roughness values were 6, 12 and 25 ?m. A decrease by almost 60{\%} in the roughness value was observed between the initial and last stage of the melted track, when using argon as shielding gas.",
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Effect of shielding gas on the properties and microstructure of melted steel surface using a TIG torch. / Munoz-Escalona, P.; Mridha, S.; Baker, T. N.

In: Advances in Materials and Processing Technologies, Vol. 1, No. 3-4, 28.01.2016, p. 435-443.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of shielding gas on the properties and microstructure of melted steel surface using a TIG torch

AU - Munoz-Escalona, P.

AU - Mridha, S.

AU - Baker, T. N.

N1 - Acceptance date: not available and added date to match earliest publication date (pub date confirms pre-REF scope). ET 23/1/20

PY - 2016/1/28

Y1 - 2016/1/28

N2 - A surface engineering technique based on a tungsten inert gas (TIG) torch was used to melt single tracks on the surface of a microalloyed steel with a hardness of 150 HV. The influence of three shielding gases, argon, helium and nitrogen, on the microstructure and hardness of the re-solidified surfaces was analysed. In all melting techniques, the heat generated by the source is normally conducted to the substrate ahead of the torch and has been described as 'preheat'. This leads to a gradually higher substrate temperature, from the start to the finish of a melted surface track. The aim of this research was to analyse any inhomogeneities in the microstructure, due to 'preheat', which is rarely considered in the published literature. Three thermocouples were located along the melted track in order to record the temperature at three different points. An energy input of ~840 J/mm was used in each experiment, and the results show that the maximum temperature recorded by the last thermocouple, No three (subjected to the preheat), for argon, helium and nitrogen gas was 590, 1120 and 740 °C, respectively, where a difference of 150 and 200 °C was registered between the first and third thermocouples when using helium and nitrogen, respectively. The corresponding hardness values were 170, 162 and 225 HV, and the corresponding surface roughness values were 6, 12 and 25 ?m. A decrease by almost 60% in the roughness value was observed between the initial and last stage of the melted track, when using argon as shielding gas.

AB - A surface engineering technique based on a tungsten inert gas (TIG) torch was used to melt single tracks on the surface of a microalloyed steel with a hardness of 150 HV. The influence of three shielding gases, argon, helium and nitrogen, on the microstructure and hardness of the re-solidified surfaces was analysed. In all melting techniques, the heat generated by the source is normally conducted to the substrate ahead of the torch and has been described as 'preheat'. This leads to a gradually higher substrate temperature, from the start to the finish of a melted surface track. The aim of this research was to analyse any inhomogeneities in the microstructure, due to 'preheat', which is rarely considered in the published literature. Three thermocouples were located along the melted track in order to record the temperature at three different points. An energy input of ~840 J/mm was used in each experiment, and the results show that the maximum temperature recorded by the last thermocouple, No three (subjected to the preheat), for argon, helium and nitrogen gas was 590, 1120 and 740 °C, respectively, where a difference of 150 and 200 °C was registered between the first and third thermocouples when using helium and nitrogen, respectively. The corresponding hardness values were 170, 162 and 225 HV, and the corresponding surface roughness values were 6, 12 and 25 ?m. A decrease by almost 60% in the roughness value was observed between the initial and last stage of the melted track, when using argon as shielding gas.

KW - surface engineering

KW - shielding gas

KW - TIG

KW - surface roughness

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DO - 10.1080/2374068X.2015.1133789

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EP - 443

JO - Advances in Materials and Processing Technologies

JF - Advances in Materials and Processing Technologies

SN - 2374-068X

IS - 3-4

ER -