Chapter 29 Shielded Metal Arc Welding 785
Copyright Goodheart-Willcox Co., Inc.
The E7018 is the most commonly used
low-hydrogen electrode. In welds that do
not require low-hydrogen qualities, the
E7018 electrodes could be used. An E6010
electrode normally deposits as much as
40 ml/100 g of hydrogen in weld metal.
Open packages of low-hydrogen
electrodes should be stored in a rod oven to
prevent the absorption of excess moisture
and preserve the low-hydrogen properties,
Figure 29-12.
Joint Types
The type of welding joint is determined
by the physical relationship of the two
pieces of metal to each other. Virtually all
welded joints can be classifi ed as butt,
T-, corner, edge, or lap joints. Each requires
different welding techniques and application
of heat, Figure 29-13.
Butt Joint
A butt joint is welded between two pieces of metal positioned
approximately in the same plane, beginning with a gap between the two
parallel edges. The welded bead is referred to as a groove weld because it
passes completely through the gap, or groove, between the two parallel
edges. In many applications, the butt joint must be welded from one side
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Figure 29-12. Rod oven for dry storage of electrodes.
Butt Corner Lap
T Edge
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Figure 29-13. Basic joint types for welding.