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Chapter 5 SMAW: Equipment and Supplies
Chapter
Chapter Chapter
5
SMAW::WAMS
EquipmenttnempiuqE
and
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SMAW:
Equipment
and Supplies and
After studying this chapter, you will be able to:

Describe the differences between direct current
(dc) and alternating current (ac).

Interpret American Welding Society (AWS)
abbreviations regarding welding current polarity.

Identify the equipment and accessories used in
shielded metal arc welding (SMAW).

Identify factors to consider when selecting an arc
welding machine.
Shielded Metal Arc Welding
Principles
Shielded metal arc welding (SMAW) is a weld-
ing process in which the base metals are heated to
fusion or melting temperature by an electric arc. The
arc is created between a covered metal electrode and
the base metal. A shielding gas protects the base
metals, arc, electrode, and weld from the atmos-
phere during welding. The shielding gas is created
as the flux covering on the electrode melts. When
the flux solidifies, it forms a protective slag over the
weld bead. The melting electrode wire furnishes
filler metal to the weld. See Figure 5-1.
alternating current (ac)
bridge rectifier
chipping hammer
constant current (CC)
constant voltage (CV)
cover plate
cycle
diode
direct current (dc)
direct current electrode
negative (DCEN)
direct current electrode
positive (DCEP)
direct current reverse
polarity (DCRP)
direct current straight
polarity (DCSP)
droop curve machines
Technical
Terms
bjectives
Learning
droopers
duty cycle
electrode holder
electrode lead
filter lens
flash goggles
frequency
gauntlet gloves
helmet
hertz
input power
inverter
lug
open circuit voltage (OCV)
polarity
primary current
rated output current
secondary current
shielding gas
shielded metal arc
welding (SMAW)
silicon-controlled
rectifier
slag
step-down transformer
terminals
voltage drop
welding outfit
welding station
wire brush
work booth
workpiece lead
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