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Effects of GTAW Pulse Condition on Penetration, Discoloration and Bending Property for Titanium Tube

GTAW 펄스 용접 조건에 따른 타이타늄 정밀관의 용입, 변색 및 굽힘특성

  • Received : 2014.11.08
  • Accepted : 2014.12.04
  • Published : 2014.12.31

Abstract

The purpose of the study is to produce a mechanically improved weld and minimum variation of color through comparing unpulsed and pulsed GTAW (Gas Tungsten Arc Welding) for pure titanium (CP grade7) tube. Pulsed GTAW using 60 A peak current and 20 A background current (1:9) achieved the wider window of welding conditions having part and full penetration without burn-through than the case of unpulsed GTAW. Moreover, the pulsed welding reduced a discoloration on the back bead of the weld and the size of microstructures (basket weave and serrated ${\alpha}$). That is because the pulsed welding has it's a low heat input and severe weld flow induced from electric current variation. Furthermore, the pulsed welding improved the bending property of the welded Ti tube. The enhanced bending property for the pulsed GTAW was due to the insignificant discoloration on the weld surface with maintaining the metal polish.

Keywords

Pulsed welding;Titanium tube;Bending;Discoloration;Hardness

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