Shielded metal arc welding is produced by heating with an electric arc created between a flux-covered metal electrode and the work. The arc creates intense heat, 7,000°F to 11,000°F, concentrated in a very small area. It results in melting of the parent metal parts, the core wire and some of the flux covering. Other elements of the flux covering decompose to form a gaseous shield around the arc. This shield protects the molten metals from contamination by the surrounding atmosphere. As the electrode melts, small drops or globules are formed, forced across the arc and deposited on the work into a molten pool which solidifies, forming a bead of weld metal.
The diver should understand that the drops or globules do not simply fall into the pool by gravity, but are forced by the electric current flow. Otherwise, overhead welding would not be possible.
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