Discuss the effects of setting the current too low or too high.
What will be an ideal response?
Each welding electrode must be operated in a specified current (amperage) range. Welding with the current set too low results in poor fusion and poor arc stability. The weld may have slag or gas inclusions because the molten weld pool was not fluid long enough for the flux to react. Little or no penetration of the weld into the base plate may also be evident. With the current set too low, the arc length is very short. A very short arc length results in frequent shorting and sticking of the electrode.
The core wire of the welding electrode is limited in the amount of current it can carry. As the current is increased, the wire heats up because of electrical resistance. This preheating of the wire causes some of the chemicals in the covering to be burned out too early. The loss of the proper balance of elements causes poor arc stability. This condition leads to spatter, porosity, and slag inclusions.
An increase in the amount of spatter is also caused by longer arc lengths. The weld bead made at a high amperage setting is wide and flat with deep penetration. The spatter is excessive and is mostly hard. The spatter is called hard because it fuses to the base plate and is difficult to remove. The electrode covering is discolored more than 1/8 in. (3 mm) to 1/4 in. (6 mm) from the end of the electrode. Extremely high settings may also cause the electrode to discolor, crack, glow red, or burn.
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What will be an ideal response?
The term standoff distance refers to the _____
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