Arcoweld ARCOSTICK MMA 180, Operator'S Manual

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OPERATION CONTROL AND CONNECTORS
14
4.4.2 Electrode selection
The electrode diameter selection is based on the workpiece thickness, welding
position, joint form, welding layer, etc. Please refer to the following table.
The welding current reference for different electrode diameter
Electrode
diameter/mm
1.6 2.0 2.5 3.2 4.0
Welding current/A 25
～
40 40
～
60 50
～
80 100
～
130
150~210
The relation between the welding current(I)’ factor(K) & electrode diameter(d) (I
＝
K
×
d: Carbon electrode)
Electrode
diameter/mm
1.6 2
～
2.5 3.2
Factor/K 20
～
25 25
～
30 30
～
40
Notice: the above parameters originate from
《
Welding Dictionary
》
P66
～
P67, Volume
1 of Edition 2.

Electrode should be dry before using.
This is to prevent hydrogen induced cold cracking. In the welding process, the arc
must not be too long; otherwise, it will cause unstable arc burning, large spatter,
light penetration, undercut, blowhole, etc. If the arc is too short, it will cause
electrode sticking.

In MMA welding the arc length is usually equal to 0.5~1.0 time of the electrode
diameter. The basic electrode’s arc length is not beyond the electrode diameter,
it’s better to choose the short arc welding method; the electrode’s arc length is
equal to the electrode diameter.
4.5 Arc Welding Defect and Prevent Method
Defect name Caused reasons Prevent methods
Welding
seam doesn’t
meet the
requirement
The groove angle is not correct.
The root face and assembly gap are not equal
Welding technics parameters are
unreasonable
The welder’s operation skill is lower
Choose the proper groove angle & assembly
gap, improve the assembly quality
Choose the proper welding parameters
Improve the operation skill of welders
Undercut
Over current
Arc length is too long
The electrode angle is wrong
Manipulation of electrode is not proper
Choose the proper welding current & speed
The arc is too long.
The electrode angle is incorrect
Manipulation of electrode should be correct