Würth MIG 180-5S Mode D'emploi Original page 33

improve weld penetration.
(see fig. H (b) on page 9)
6.3 Welding position
Flat position is easiest of the welding positions
and is most commonly used. It is best if you can weld
in the flat position if at all possible as good results
are easier to achieve.
(see fig. I (a) on page 9)
Horizontal position is performed very much the
same way as the flat weld except that the angle B
(see "HOLDING THE TORCH") is such that the wire,
directed more towards the metal above the weld joint
is to help prevent the weld puddle from running down-
wards while still allowing slow enough travel speed.
A good starting point for angle B is about 30 degrees
DOWN from being perpendicular to the workpiece.
Vertical position is easier for many people since
it involves pulling the torch from top to bottom. It can
be difficult to prevent the puddle from running down-
wards. Pushing the torch from bottom to top may pro-
vide better puddle control and allows slower rates of
travel speed to achieve deeper penetration. When
vertical welding, angle B (see "HOLDING THE
TORCH") is usually always kept at zero, but angle A
will generally range from 45 to 60 degrees to provide
better puddle control.
(see fig. I (b) on page 9)
Overhead position is the most difficult welding
position. Angle A (see "HOLDING THE TORCH")
should be maintained at 60 degrees. Maintaining
this angle will reduce the chances of molten metal
falling into the nozzle. Angle B should be held at
zero degrees so that the wire is aiming directly into
the weld joint. If you experience excessive drip-
ping of the weld puddle, select a lower heat setting.
Also, the weave bead tends to work better than the
stringer bead.
(see fig. I (c) on page 9)
6.4 Multiple pass welding
Butt Weld Joints. When butt welding thicker mate-
rials, you will need to prepare the edges of the mate-
rial to be joined by grinding a bevel on the edge
of one or both pieces of the metal being joined.
When this is done, a "V" groove is created between
the two pieces of metal that will have to be closely
welded. In most cases more than one pass or bead
will need to be laid into the joint to close the "V"
groove.
Laying more than one bead into the same weld joint
is known as a multiple-pass weld.
Fig. J on page 9 shows the sequence for laying
multiple pass beads into a single "V" butt joint.
NOTE:
When using self-shielding flux-core wire it
is very important to thoroughly chip and brush the
slag off each completed weld bead before making
another pass or the next pass will be of poor quality.
Fillet Weld Joints. Most fillet weld joints, on met-
als of moderate to heavy thickness, will require multi-
ple pass welds to produce strong joint. The illustrations
in fig. K on page 9 show the sequence of laying mul-
tiple pass weld beads into a Lap fillet joint (a) and a
T fillet joint (b).
6.5 Spot welding
There are three methods of spot welding: Burn-Through,
Punch and Fill, and the Lap Spot type. Each method
has advantages and disadvantages depending
on the specific application as well as the personal
preference.
The Burn Through method welds two over-
lapped pieces of metal together by burning through
the top piece and into the bottom piece. When using
the Burn-Through method, larger wire diameters tends
to work better than smaller diameters. Wire diameters
that tends to work best, using the burnthrough method
are 0.9 mm self-shielding flux-core wires. Do not use
0.75 mm self-shielding flux core wires when using the
burn-through method unless the metal is VERY thin or
excessive filler metal build-up and minimal penetra-
tion is acceptable. Always select the HIGH heat set-
ting with the burnthrough method and tune in the wire
speed prior to making any spot welds.
(see fig. L (a) on page 9)
The Punch and Fill method produces a weld
with the most finished appearance of the three spot
weld methods. In this method, a hole is punched
or drilled into the top piece of metal and the arc is
directed through the hole to penetrate into the bot-
tom piece. The puddle is allowed to fill up the hole
leaving a spot weld that is smooth and flushed with
the weld surface established on the top piece. Select
the right wire diameter, heat setting, and tune in the
wire speed as if you were welding the same thick-
ness material with a continuous bead.
(see fig. L (b) on page 9)
The Lap Spot method directs the welding arc
to penetrate both the bottom and the top piece at
the same time, right along each side of the lap joint
seam. Select the right wire diameter, heat setting,
and tune in the wire speed as if you were welding
the same thickness material with a continuous bead.
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