Yeswelder CT2050 Operator's Manual page 40

BASIC KNOWLEDGE OF WELDING
a) Flat Welding b) Vertical Welding
Fig 19 Posture in Welding
3) Arc Igniting
Arc igniting is the process of producing a stable arc between electrode and workpiece in order to heat them to implement welding.
Common arc ignition mode includes scraping mode and striking mode. (See Fig.20) During welding, touch the surface of the
workpiece with the end of the electrode by scraping or light striking to form a short circuit, and then quickly lift the electrode 2~4mm
away to ignite the arc. If arc ignition fails, it is probably because there is coating at the end of the electrode, which affects the electric
conduction. In this case, the operator can strongly knock the electrode to remove the insulation material until the metal surface of
the core wire can be seen.
a) Striking Mode b) Scraping Mode
Fig 20 Arc Extinguishing Modes
4) Tack Weld
For fixing the relative positions of the two pieces of weldment and welding conveniently, 30~40mm short weld joints are welded ev-
ery certain distance in order to fix the relative positions of the workpiece during welding assembly. This process is named tack weld.
5) Electrode Manipulation
The electrode manipulation actually is a resultant movement in which the electrode simultaneously moves in three basic directions:
the electrode gradually moves along the welding direction; the electrode gradually moves toward the weld crater, and the electrode
transversely swings. (See Fig 21) Electrode should be correctly manipulated in three movement directions after the arc is ignited. In
butt welding and flat welding, the most important is to control the following three aspects: welding angle, arc length, and welding
speed.
(1) Welding angle: the electrode should be inclined 70～80º forwards. (See Fig 22)
(2) Arc length: the proper arc length is equal to the diameter of the electrode in general.
(3) Welding speed: proper welding speed should make the crater width of the weld bead about twice the diameter of the electrode,
and the surface of the weld bead should be flat with fine ripples. If the welding speed is too high, and the weld bead is narrow and
high, the ripples are rough, and the fusion is not well implemented. If the welding speed is too low, the crater width is excessive, and
the workpiece is easy to be burned through. Besides, the current should be proper, the electrode should be aligned, the arc should
be low, and the welding speed should not be too high and should be kept uniform during the whole welding process.
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