• Title/Summary/Keyword: 텅스텐 불활성가스 용접

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A study on the titanium welding process according to the temperature characteristics of shielding methods (티타늄 용접공정에서 온도특성에 따른 실딩방법에 관한 연구)

  • Chung, Han-Shik;Jeong, Hyo-Min;Lee, Dae-Chul;Lee, Byeong-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.1
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    • pp.29-34
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    • 2013
  • The welds tent to be weakened if it is exposed to the air during the welding process. In titanium welding with Gas Tungsten Arc Welding, inappropriate colors of the welds, such as purple/red, blue, yellow, gray, white and pink represents that it is contaminated by oxygen and nitrogen in the air. Shielding gases can be used to protect welds from the contamination. In addition, Weld metal and heat affected zone (HAZ) are also shielded from the air when it is cooled down to the room temperature. In this paper, appropriate shielding gases for the shape and form of Trailing Shielding Jig and torch shielding ($13{\sim}20{\ell}/min$), after shielding ($22{\sim}30{\ell}/min$), and back shielding ($25{\sim}30{\ell}/min$) are studied.

A Characteristics of Thick and Hard Al-Cu Alloy by Overlaying Welding Process (오버레이 용접법에 의한 Al-Cu 합금 경화후막의 특성)

  • 박정식;양변모;박경재
    • Journal of Welding and Joining
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    • v.14 no.4
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    • pp.53-61
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    • 1996
  • It was attempted to improve the wear resistance of Al alloy under the load condition by making a formation of the thicker surface hardening alloy layers. The thicker surface hardening alloy layers were formed on 6061 Al alloys overlayed by MIG and TIG welding process with Cu powders feeding. The characteristics of hardening and wear resistance have been investigated in relation to the microstructures of alloyed layers, with a selection of optimum alloying conditions for formation of overlaying layer. The results obtained were summarized as follows With increasing feeding rate of Cu powders by MIG welding, the hardness and specific wear of the overlay weld alloys were increased. It is considered that these high hardness and specific wear of overlay weld alloys were due to the formation of Θ($Al_2Cu$) phases. With increasing feeding rate of Cu powders by TIG welding, the hardness and specific wear of the overlay weld alloys were increased in feeding rates 12 and 18g/min. However, the hardness and specific wear were decreased in the powder feeding rate 38g/min. It is considered that considered that decrease of hardness and specific wear in the powder feeding rate 38g/min due to formation of ${\gamma}$($Al_4Cu_9$) phases.

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Electrochemical Evaluation of Corrosion Property of Welding Zone of 304 Stainless Steel (304 스테인리스강의 용접부위의 부식특성에 관한 전기화학적 평가)

  • Moon, Kyung-Man;Kim, Yun-Hae;Kim, Jong-Do;Lee, Myung-Hoon;Kim, Jin-Gyeong
    • Journal of Ocean Engineering and Technology
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    • v.23 no.4
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    • pp.58-63
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    • 2009
  • Two kinds of welding methods are used for austenitic 304 stainless steel: laser welding and TIG welding. The difference in the corrosion characteristics of the welded zone between these two welding methods was investigated using electrochemical methods, such as corrosion potential measurements, polarization curves, cyclic voltammograms, etc. The Vickers hardnesses of all the welded zones (WM: Weld Metal, HAZ: Heat Affected Zone, BM: Base Metal) showed relatively higher values in the case of laser welding than for TIG welding. Furthermore, the corrosion current densities of all the welding zones showed lower values compared to TIG welding. In particular, the corrosion current density of the HAZ with TIG welding had the highest value of all the welding zones, which suggests that chromium depletion due to the formation of chromium carbide appears in the HAZ, which is in the range of the sensitization temperature. Thus, it can easily be corroded with a more active anode. Consequently, we found that the corrosion resistance of all of the welding zones for austenitic 304 stainless steel could apparently be improved by using Laser welding.

Electrochemical Evaluation on Corrosion Property of Welding Zone of 22APU Stainless Steel (22APU 스테인리스강의 용접부위의 부식특성에 관한 전기화학적 평가)

  • Moon, Kyung-Man;Kim, Yun-Hae;Lee, Sung-Yul;Kim, Jong-Do;Lee, Myung-Hoon;Kim, Jin-Gyeong
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1162-1169
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    • 2009
  • Two kinds of welding methods were carried out for 22APU stainless steel, one is a Laser welding and the other is the TIG welding. In this case, difference of corrosion characteristics of welded zone with two welding methods mentioned above was investigated with electrochemical methods such as measurement of corrosion potential, polarization curves and cyclic voltammogram etc.. Vickers hardness of all welded zone (WM:Weld Metal, HAZ:Heat Affected Zone, BM:Base Metal)in the case of Laser welding showed a relatively higher value than those of TIG welding. Futhermore their corrosion current density in all welding zone were also observed with a lower value compared to TIG welding. In particular corrosion current density of BM regardless of welding method indicated the lowest value than those of other welding zone. Intergranular corrosion was not observed at the corroded surface of all welding zone in the case of Laser welding, however it was observed at WM and HAZ with TIG welding, which is suggested that chromiun depletion due to forming of chromium carbide appears to WM and HAZ which is in the range of sensitization temperature. Therefore their zone can easily be corroded with more active anode. Consequently we can see that corrosion resistance of all welding zone of 22APU stainless steel can apparently be improved by using of Laser welding.