Lincoln Electric LTW1 manual Welding In The Vertical Position, Penetration, Fillet Joints

5 LEARNING TO WELD 5

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° CENTERLINE OF GUN TO HORIZONTAL PLATE

Welding In The Vertical Position

Welding in the vertical position can be done either ver- tical-up or vertical-down. Vertical-up is used whenever

alarger, 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 cause for fast, low penetrating welds.

WARNING

Use of this unit on thicker materials than recom- mended 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 lap- ping" and is some what similar to a cold solder joint. Weld failure may result.

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Vertical-up And Overhead Welding

The problem, 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 per- pendicular may be required if porosity becomes a problem.

FIGURE 10

3/16 INCH AND THINNER

1/4 INCH AND THICKER

PROPER GUN ANGLE
FOR GMAW PROCESS	PROPER GUN ANGLE
WELDING IN THE VERTICAL DOWN POSITION	FOR FCAW PROCESS
	WELDING IN THE VERTICAL UP POSITION