Firepower MST 220i, Operating Manual

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FIREPOWER MST 220i
BASIC WELDING 4-2 Manual 0-5343
Horizontal Fillet Weld
Direction of
Travel
5° to 15°
Longitudinal Angle
30° to 60°
Transverse Angle
Art # A-08994
Figure 4-5
Vertical Fillet Welds
Art # A-08995
30° to 60°
Transverse
Angle
30° to 60°
Transverse
Angle
Direction of Travel
10°
Longitudinal Angle
10° to 20° Longitudinal
Angle
Figure 4-6
Overhead Weld
Art # A-08996
30° to 60°
Transverse Angle
Direction of Travel
5° to 15°
Longitudinal
Angle
Figure 4-7
Distance from the MIG Gun Nozzle to the Work
Piece
The electrode wire stick out from the MIG Gun nozzle
should be between 3/8" - 3/4" (10 - 20 mm). This dis-
tance may vary depending on the type of joint that is
being welded.
Travel Speed
The speed at which the molten pool travels influences
the width of the weld and penetration of the welding run.
MIG Welding (GMAW) Variables
Most of the welding done by all processes is on carbon
steel. The items below describe the welding variables in
short-arc welding of .023 - 1/4" (0.6 mm - 6.4 mm) mild
sheet or plate. The applied techniques and end results
in the GMAW process are controlled by these variables.
Preselected Variables
Preselected variables depend upon the type of material
being welded, the thickness of the material, the welding
position, the deposition rate and the mechanical proper-
ties. These variables are:
• Type of electrode wire
• Size of electrode wire
• Type of gas (not applicable for FCAW self shielding
wires)
• Gas flow rate (not applicable for FCAW self shield-
ing wires)
Primary Adjustable Variables
These control the process after preselected variables
have been found. They control the penetration, bead
width, bead height, arc stability, deposition rate and
weld soundness. They are:
• Arc Voltage
• Welding current (wire feed speed)
• Travel speed
Secondary Adjustable Variables
These variables cause changes in primary adjustable
variables which in turn cause the desired change in the
bead formation. They are:
1. Sick-out (distance between the end of the con-
tact tube (tip) and the end of the electrode wire).
Maintain at about 3/8" (10 mm) stick-out
2. Wire Feed Speed. Increase in wire feed speed
increases weld current, Decrease in wire feed
speed decreases weld current.
Art # A-08997_AD
Gas Nozzle
Electrode Wire
Average Arc Length
Electrode Stick-Out
Tip to
Work Distance
Actual Stick-out
Contact Tip (Tube)
Figure 4-8
3. Nozzle Angle. This refers to the position of the
MIG Gun in relation to the joint. The transverse
angle is usually one half the included angle be-
tween plates forming the joint. The longitudinal
angle is the angle between the centre line of the
MIG Gun and a line perpendicular to the axis of
the weld. The longitudinal angle is generally
called the Nozzle Angle and can be either trail-
ing (pulling) or leading (pushing). Whether the
operator is left handed or right handed has to be
considered to realize the effects of each angle
in relation to the direction of travel.