1. GMA process development for pore-free zinc-coated steel sheet welding in automotive industry.
- Author
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Han, Sang-Woo, Kim, Hansol, Lee, Geonho, Shin, Seungcheol, Jeon, Jongho, Han, Sangjun, Bae, Gyuyeol, and Cho, Jungho
- Subjects
STEEL welding ,GAS metal arc welding ,WELDING industry ,SHEET-steel ,VACUUM arcs ,AUTOMOBILE industry ,WIRE - Abstract
In GMAW (gas metal arc welding) of Zn (zinc)-coated steel sheets, defects such as pores occur in the weld due to trapped Zn vapor. To solve this problem, we investigated the pore-free welding condition using conventional solid wire. We verified through experiments that the combination of 20% CO
2 -Ar shielding gas and DCEP (direct current electrode positive) polarity has a higher pore-free performance than other combinations. A higher performance of pore-free welding was obtained by reducing the CTWD (contact tip to work distance) and using ER70S-3 wire. In conclusion, the optimized welding conditions at 10 mm overlap, 80 cm/min welding speed, and 30° work angle are 160 A arc current, 20 V voltage, 15 mm CTWD, 10° push angle, DCEP polarity, 20% CO2 -Ar shielding gas with 20 L/min flow rate, and ER70S-3 wire type. For flow pattern analysis, a high-speed camera with blue laser was used, and it was observed that a longer weld pool and smaller droplets could improve the efficiency of Zn vapor emission. With ER70S-3, a longer weld pool can be obtained, as it has a lower viscosity due to lower percentages of Si and Mn in its composition. [ABSTRACT FROM AUTHOR]- Published
- 2023
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