Study on CMT welding technology of a steel in automotive manufacturing: weld bead geometry mechanical property and welding metallurgy
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Date
2018Author
Niwat Mookam
Uraiwan Pongsa
Phoometh Sangrayub
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In this research, the objective was to investigate and measure the weld bead
geometry, mechanical property, and welding metallurgy when JIS G3113 steel are
welded using CMT. The study examines a number of welding variables, including
weld current ( 10, 12, 14, 16, and 18 V) , and weld travel speed ( 25, 50, 75, 100, and
125 mm/min). The experiment was run using a CMT welding machine under an argon
atmosphere. The quality of welded specimens was determined by their weld bead
height, bead width, penetration, strength and microstructure.
The optimal welding conditions were found to be 12 V of weld current and
25 mm/min of weld travel speed. The optimal welding conditions provided weld
bead geometry and strength of quality which were able to pass the specifications of
the making and inspecting welds on automotive steel. However, the welding travel
speed no influence on the bead geometry, while the weld bead height, bead width
and penetration exhibited a non-uniform pattern. After welding, only an Fe
0.9 intermetallic compound was observed in the microstructures. In addition, the larger
degree of preferred orientation was detected at the {100} plane with a increase
residual strain in the microstructure.