7.4 Mechanism and Influencing Factors of Stability of Dual-Beam Welding
197
Fig. 7.15 Evolution curves
of keyhole depth-time with
parallel dual beams in
different processes
(a) Different welding speeds
( b) Different spot spacing
Keyhole depth δ/mm
Time t/ms
Keyhole depth δ/mm
Time t/ms
Beam spot spacing = 0.25 mm
Beam spot spacing = 0.5 mm
Beam spot spacing = 1.0 mm
beam welding with different welding speeds and different spot spacing. It can be
seen that in certain welding process, the keyhole oscillates violently in welding, with
its depth roughly divided into three stages: ➀ linear increase stage, in which the
keyhole depth grows rapidly in a linear way; ➁ oscillatory increase stage, in which
the growth rate of keyhole depth slows down, accompanied by small oscillation; ➂
stable oscillation stage, in which the keyhole depth remains at a relatively fixed value
and oscillates violently up and down.
7.4.2.4 Periodicity of Keyhole Depth Oscillation
Figure 7.16 shows the oscillation curves of keyhole depth within 30–35 ms in the
welding process with different spot spacing. It can be seen that after the keyhole