10 A Novel High-Efficiency Keyhole Tungsten Inert Gas …
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Fig. 10.33 Geometry profile of the weld under different welding currents [38]
10.4.1.1 Welding Current
Under different welding currents, the GP of the weld is displayed in Fig. 10.33.
When other parameters remain unchanged and only the welding current is changed,
the W and D increase as the welding current increases. When the welding current
is low, the penetration ability of the arc is weak. Therefore, welding pores appear
in the weld when the welding current is 470 A. As the welding current increases,
the penetration ability of the arc gradually increases. A keyhole mode was produced
during the welding process, and the pores disappeared. However, when the welding
current is large enough, due to excessive heat input, the balance between the static
pressure of the liquid metal in the welding pool and the surface tension is destroyed
[38]. The weld pool collapsed, and D of the weldment on the back was too high.
Therefore, suitable welding current is a key factor affecting the welding quality.
10.4.1.2 Welding Speed
Figure 10.34 displays the GP of weld under different welding speeds. When the other
parameters remain unchanged, the W and D increase as the welding speed decreases.
When the welding speed is varied between 210 mm/min and 240 mm/min, the welds