Types of Welds, Welding Procedures | Lincoln Electric IM366-B

steel can usually be easily welded without special pre- cautions. Some steels, however, contain higher car- bon levels or other alloys and are more difficult to weld. Basically, if a magnet sticks to the metal and if you can easily cut the metal with a file, chances are good that you will be able to weld the material with the

SP-100. For further information on identifying various types of steels and other metals, and for proper proce- dures for welding them, we again suggest you pur- chase a copy of “New Lessons in Arc Welding” (see page 29).

Regardless of the type of metal being welded, it is important in order to get a quality weld that it be free of oil, paint, rust or other contaminant's.

TYPES OF WELDS

Five types of welding joints are: Butt Welds, Fillet Welds, Lap Welds, Edge Welds and Corner Welds.

Of these, the Butt Weld and Fillet Weld are the two most common welds.

Butt weld

Lap weld

Edge weld

Fillet weld

Corner weld

WELDING PROCEDURES

Butt Welds

Place two plates side by side, leaving a space approx- imately one half the thickness of the metal between them in order to get deeper penetration.

Securely clamp or tack weld the plates at both ends, otherwise the heat will cause the plates to move apart (see drawing):

Now weld the two plates together. Weld from left to right (if right handed). Point the wire electrode down in the crack between the two plates, keeping the gun slightly tilted in the direction of travel.

Watch the molten metal to be sure it distributes itself evenly on both edges and in between the plates.

Penetration

Unless a weld penetrates close to 100% of the metal thickness, a butt weld will be weaker than the material welded together. In this example, the total weld is only half the thickness of the material; thus the weld is only approximately half as strong as the metal.

Poor

In this example, 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.

Good

Fillet Welds

When welding fillet welds, 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.

45˚

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. Vertical-down is used primarily on sheet metal 5/32" (3.9 mm) and under for fast, low penetrating welds.

WARNING

Use of the SP-100 on thicker materials than rec- ommended may result in poor welds. The welds may “look” good, but may just be “sitting” on top of the plate. This is called “Cold Casting” and will result in weld failure. See Recommended Processes and Equipment.

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