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

Min, Seonghwan; An, Sungyong; Park, Jitae; Park, Youngdo; Kang, Namhyun

doi:2014.32.6.583

J Weld Join > Volume 32(6); 2014 > Article

Research Paper

Journal of Welding and Joining 2014;32(6):583-591.
DOI: https://doi.org/10.5781/JWJ.2014.32.6.47 Published online December 31, 2014.

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

Seonghwan Min^*, Sungyong An^**, Jitae Park^***, Youngdo Park^****, Namhyun Kang^**

Correspondence: Namhyun Kang,
Email: nhkang@pusan.ac.kr

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 α). 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.

Key Words: Pulsed welding, Titanium tube, Bending, Discoloration, Hardness