Selco RC10 Instrucciones De Uso página 26

10.2 Summary of the selections and the parameters for MMA welding
MMA
CHOICE
ELECTRODE
TYPE
PARAMETER DESCRIPTION
Weld current Welding current
Arc Force Percentage increase
of the welding cur-
rent supplied by the
generator in the case
of a short circuit.
Hot Start Percentage increase
of the welding cur-
rent supplied by the
generator
moment of starting.
26
CHOICE
WELDING
ELECTRODE
PARAMETERS
DIAMETER
NOTES
The value of the
welding current is
calculated by the
machine according
to the type o electro-
de chosen.
Higher welding cur-
rents generally cor-
respond to electro-
des of a greater dia-
meter.
A higher arc force
value makes
welding more reacti-
ve.
A higher value facili-
tates the arc strike.
at the
11.0 DESEAMING PROCEDURE (ARC-AIR)
With the use of suitable equipment, an industrial welding machi-
ne with a sufficient power and operating voltage of 40÷55V can
be used to cut steel, cast iron and copper alloys, and to carry out
surface work on these materials, such as, for example, grooving
and removal of cracks.
The process, known as "air carbon arc cutting", uses a special
electrode-holding torch which directs a powerful jet of compres-
sed air onto the area, that removes the material melted by the
heat from the arc itself. The electrodes mainly used with direct
current generators are made of compressed mixtures of carbon,
graphite and binders with a covering of copper. Each torch requi-
res a particular flow rate and pressure for the compressed air cir-
cuit; with manual torches for small powers (up to 600A), a pres-
sure of between 5 and 7 atmospheres is required, and a capacity
of about 500 litres/min. The electrode is kept slanted and pus-
hed in the cutting direction, so as to facilitate the removal of the
melted material.
The bigger the angle between the electrode and the workpiece
the bigger will be the incision: as a guide, for engraving a groove
it will be between 35° and 70°, for cutting, between 70° and 80°,
for deseaming and surface finishing between 15° and 70°. In the
table are shown the currents required by the electrodes accor-
ding to their diameter; the maximum current shown is that
the
recommended. The distance bewteen torch and electrode point
must never be more than 15 centimetres, and must be reduced
by at least half with nonferrous materials.
DIAMETER
ELECTRODE
(mm)
4
4.76
6.35
8
9.5
12.7
15.8
19
Table for selecting the electrode in ARC-AIR process
11.1 Parameter selection and regolation of gouging process (Arc-Air)
Select the arc-air process.
IMPORTANT: the process works only on Genesis 503 GSM
MINIMUM MAXIMUM
(A) (A)
80 150
110 200
150 350
200 450
300 600
600 1000
800 1200
1200 1600