Penetration; Fillet Joints; Welding In The Vertical Position; Vertical-Up And Overhead Welding - Lincoln Electric LTW1 Manual De Instrucciones

LEARNING TO WELD

Penetration

Unless a weld penetrates close to 100% of the metal thickness, a butt
joint will be weaker than the material welded together. In the example
shown in Figure 7, the total weld is only half the thickness of the
material thus the weld is only approximately half as strong as the
metal.
FIGURE 7
FIGURE 8
In the example shown in Figure 8, the joint has been welded so that
100% penetration could be achieved. The weld, if properly made, is
as strong as or stronger than the original metal.

Fillet Joints

When welding fillet joints, it is very important to hold the wire
electrode at a 45° angle between the two sides or the metal will not
distribute itself evenly. The gun nozzle is generally formed at an angle
to facilitate this. See Figure 9.
FIGURE 9
45¡ CENTER LINE
45° CENTERLINE OF GUN TO
TO HORIZONTAL PLATE
HORIZONTAL PLATE
WELDING IN THE
VERTICAL POSITION
Welding in the vertical position can be done either vertical-up or
vertical-down. Vertical-up is used whenever a larger, stronger weld is
desired 1/4"(6.4mm) and thicker material. Vertical-down is used
primarily on sheet metal 3/16"(4.8mm) and thinner materials for fast,
low penetrating welds.
WARNING
Use of this unit on thicker materials than recommended may
result in welds of poor quality. The welds may appear to be
fine, but may lack the fusion or bonding necessary to give a
strong weld. This is called "cold casting" or "cold lapping"
and is somewhat similar to a cold solder joint. Weld failure
may result.

Vertical-up And Overhead Welding

The challenge, when welding vertical-up 1/4"(6.4mm) and thicker
material, is to put the molten metal where it is wanted and make it
stay there. If too much molten metal is deposited, gravity will pull it
down-wards and make it "drip." Therefore, a certain technique has to
be followed.
When welding out-of-position, run stringer beads. Don't whip, break
the arc, move out of the puddle, or move too fast in any direction. Use
Wire Feed Speed (WFS) in the low portion of the range. The general
technique and proper gun angle is illustrated in Figure 10.
Generally, keep the electrode nearly perpendicular to the joint as
illustrated. The maximum angle above perpendicular may be required
if porosity becomes a problem.
FIGURE 10
3/16 INCH AND THINNER
PROPER GUN ANGLE
FOR GMAW PROCESS
WELDING IN THE VERTICAL DOWN POSITION
5
1/4 INCH AND THICKER
PROPER GUN ANGLE
FOR FCAW PROCESS
WELDING IN THE VERTICAL UP POSITION