Welding - Chapters 1-6 - First Exam with
Complete Solutions
List welding Currents:
AC,DC-,DC+
What is the Definition of welding current
the current in the welding circuit during the making of the weld.
Three units
...
Welding - Chapters 1-6 - First Exam with
Complete Solutions
List welding Currents:
AC,DC-,DC+
What is the Definition of welding current
the current in the welding circuit during the making of the weld.
Three units are used to measure welding current
Voltage: electrical pressure
Amperage: number of electrons flowing
Wattage: power of the arc
What approximately is The temperature of the arc?
11,000°F (6000°C).
Three different types of current used for welding are
Alternating Current: evenly distributed between (+) and (-)
Direct-Current Electrode Positive: electrode positive, ground (work) negative
Direct-Current Electrode Negative: electrode negative, ground (work) positive
the voltage at the electrode before striking an arc (no current being drawn)
Open-circuit voltage
Operating voltage
the voltage at the arc during welding
Arc blow
the deflection of the arc from its normal path because of magnetic forces.
Duty Cycle
percentage of time a welding machine can be used continuously at maximum amperage
AC
Alternating Current
AWS stands for
American Welding Society.
5 basic welding joints are
lap, tee, edge, corner, butt
4 welding positions are
flat, horizontal, vertical, and overhead
2 ways to strike an arc are
tapping and scratching
the distance the arc must jump from the end of the electrode to the plate or weld pool surface is?
Arc length
What Is The Measurement of the electrode to the surface of the metal?
Electrode angle
a straight weld with little or no side-to-side motion
stringer bead
A tack weld holds pieces together until
final welding can take place.
DC+ vs DCDC+ will mean the current flows from the electrode to the base metal. This creates more heat at
the electrode which creates less penetration but results in a better deposition. DC- gives you
better penetration into the base metal but less filler metal is deposited.
Conventional Flow Theory
Starts at the positive and flows towards the negative. This is commonly illustrated in diagrams,
but is not recognized as the chosen theory.
Electron Flow Theory
Theory which states electrons flow from negative to positive
weld
"a localized coalescence (the fusion or growing
together of the grain structure of the materials being
welded) of metals or nonmetals produced either by heating the materials to the required welding
temperatures,
with or without the application of pressure, or by the
application of pressure alone, and with or without the use
of filler materials.".
smaw
Shielded metal arc welding (SMAW) - also known as "stick welding", uses an electrode that has
flux, the protectant for the puddle, around it. The electrode holder holds the electrode as it slowly
melts away. Slag protects the weld puddle from atmospheric contamination.
gtaw
Gas tungsten arc welding... TIG..heliarc...manual welding process that uses a non-consumable
tungsten electrode, an inert gas, and a separate filler material.
gmaw
Gas metal arc welding (GMAW) - commonly termed MIG (metal, inert gas), uses a wire feeding
gun that feeds wire at an adjustable speed and flows an argon-based shielding gas or a mix of
argon and carbon dioxide (CO2) over the weld puddle to protect it from atmospheric
contamination.
FCAW
Flux-cored arc welding (FCAW)
forge weld
the most ancient welding processes, is a solid-state welding process that joins two pieces of
metal by heating them to a high temperature and then hammering them together
elihu thomson
inventor of arc welding in 188
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