Page 66 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

Welding Processes

Figure 5.3 Constant current characteristic
decreases. The current decrease is very small and will have
little effect on the burn-off rate of the electrode.
. As arc length decreases, voltage decreases and current
increases. The current increase is very small and will have
little effect on the burn-off rate of the electrode.
Consumables
The only consumables are flux-coated electrodes. These are
three main types:
. Basic electrodes. Basic electrodes contain calcium com-
pounds such as calcium carbonate and calcium fluoride in
the flux coating. These compounds are helpful for all
positional welding as they help produce a fast freezing slag
covering on the weld metal. The shielding gas produced
from the melting flux to protect the welding arc is mainly
CO 2 .

51

Woodhead Publishing Ltd – A Quick Guide to Welding and Weld Inspection
Data Standards Ltd, Frome, Somerset – 17/9/200905QG Welding chap5.3d Page 51 of 66