Weldclass WeldForce WF-205MST, Руководство по эксплуатации

Страница: 56 / 80

.
56 © Weldclass 2019 | E.&O.E. | Edition 2.1
12.7.4 Arc Length
As soon as the arc is established, maintain a 1.6mm to 3.2mm gap between the burning electrode end
and the parent metal. Draw the electrode slowly along as it melts down. The securing of an arc length
necessary to produce a neat weld soon becomes almost automatic. You will find that a long arc produces
more heat.
A very long arc produces a crackling or spluttering noise and the weld metal comes across in large,
irregular blobs. The weld bead is flattened and spatter increases. A short arc is essential if a high quality
weld is to be obtained although if it is too short there is the danger of it being blanketed by slag and the
electrode tip being solidified in. If this should happen, give the electrode a quick twist back over the
weld to detach it.
12.7.5 Rate of Travel
After the arc is struck, your next concern is to maintain it, and this requires moving the electrode tip
towards the molten pool at the same rate as it is melting away. At the same time, the electrode has to
move along the plate to form a bead.
The electrode is directed at the weld pool at about 20º from the vertical. The rate of travel has to be
adjusted so that a well-formed bead is produced.
If the travel is too fast, the bead will be narrow and strung out and may even be broken up into individual
globules. If the travel is too slow, the weld metal piles up and the bead will be too large.