Chapter 10 & 11 Study Guide
When first introduced, SMAW was immediately accepted because it was more productive than GTAW and produced higher quality welds than GMAW.
False
The exact shielding gas ________ required for a certain job will vary depending upon the welding conditions.
Flow rate
While less likely to be automated, _____ welding equipment can be automated easily.
GMA
MIG, MAG, and wire welding are other names for ______
GMAW
______ transfer can be used on thin materials and at a very low current range.
Globular
With the addition of ____ to the argon gas, the transfer becomes progressively more _____
Helium, globular
Slight changes in the welding gun angle can be used to control the weld as the groove spacing changes
True
The amount of reactive gas required to produce the desired effects is quite small
True
The heat produced during GMA welding is sufficient to force 100% penetration consistently, making it ideal for industrial applications.
True
The heat produces during axial spray welding using large diameter wire or high current may be intense enough to shatter the filter lens in welding helmet.
True
The same equipment may be used for semiautomatic GMAW, FCAW, and SAW
True
In GMA welding, the voltage is set ____ and the amperage is set ______
On the welder, by changing the wire-feed speed
A weld that is high and has little or no fusion is too "cold." To correct this _______.
stop welding and make the needed adjustments
GMA welding machines have ______ duty cycle
100 percent
As much as _____ can be added to the argon to increase the power in the arc without affecting the desirable qualities of the spray mode.
80% helium
In axial spray metal transfer, the shielding gas is usually a mixture of ________
95% to 98% argon and 2% to 5% oxygen
Vertical down welds should be used on thin sheet metals
False
Pulsed-arc welding systems were developed in the 1960's
True
Which of the following gases is the least dense?
Argon
When used as pure gases for welding ferrous metals, _____ may produce an erratic arc action, promote undercutting, and result in other flaws.
Argon and helium.
The shielding gas used on carbon steel is ______
Carbon dioxide, or a mixture of carbon dioxide and argon
Electrode wire has a natural curve that is known as its _____.
Cast
The _____ of a wire is measured by the diameter of the circle that the wire would make if it were loosely laid on a flat surface
Cast
The correct flow rate of a shielding gas can be set by _______
Checking welding guides
GMAW power supplies are _____ type machines
Constant-voltage constant-potential
Shielding gases in the gas metal arc process are used primarily to protect the molten metal from oxidation and ________
Contamination
To make threading electrode wire easier, _____.
Cut off about 12 in. of the end of the wire.
________ is the chief determinant of how effective a gas is for arc shielding.
Density
The _____ rate is the measure of the weld metal deposited
Deposition
The equipment for ___ is more likely to be automated
FCAW and SAW
As the slope increases, both the short circuit current and pinch effect are increased
False
Helium is not considered to be an inert gas
False
Hot-Rolled steel has a thin copper layer which is formed during the rolling process.
False
It is possible to make acceptable welds with the wrong type of power supply
False
The lower the density of a gas, the lower the flow rate required for equal arc protection
False
The short circuiting process works better with a long electrode stickout
False
Which of the following is true of axial spray transfers using high current settings?
High current settings may cause the weld to be difficult to control in out-of-position welds.
______ provide the necessary shielding because they do not form compounds with any other substance.
Inert gases
Which of the following is true of backhand welding?
Is has good bead visibility and makes welds with deeper joint penetration
Which of the following is true of perpendicular welding technique?
It has a good balance between penetration and reinforcement and is used on automated welding.
Which of the following is true of short-circuiting arc metal transfer in the overhead position?
It has less molten weld pool sag
Which of the following is true of globular transfer?
It is used in combination with pulsed-spray transfer
______ is series of ridges cut into the groove
Knurling
An advantage of the ____ feed system is that the bulky system of gears is eliminated
Linear
Which of the following tasks is done by a machine?
Maintaining the arc in semiautomatic welding processes.
Which is the following deoxidizing elements is weak?
Manganese
MAG is short for _____
Metal active gas welding
_________ is a thin layer of dark gray or black iron oxide formed during the rolling process.
Mill scale
A ______ gap may require _____.
Narrow, more penetration
In the pulsed arc metal transfer current cycle, ____ refers to the surging electrical current passing through the transformer like a wave on water
Overshoot
Adding oxygen or carbon dioxide to an inert gas causes the shielding gas to become _____, which may cause _____ in some ferrous materials
Oxidizing, porosity
_____ is increased and ____ is decreased as the electrode extension is shortened.
Penetration, buildup
Which of the following tasks are done by the welder?
Providing the joint guidance in machine welding processes
In the _____ feed systems, the electrode must have enough strength to be pushed through the conduit without kinking.
Push-type
In the pulsed arc metal transfer current cycle, _______ is a function of the time it takes the magnetic field in the transformer to collapse once the coil is de-energized
Ramp down
In the pulsed- arc metal transfer current cycle, ______ refers to how the electric current in a transformer takes a few milliseconds to build up the magnetic field to full strength once the coil is energized.
Ramp up
The rate of voltage decreases as the amperage increases within the working range is known as _____
Slope
The major advantages of the vertical down position technique are ____.
Speed, shallow penetration, and good bead appearance.
With the feed running, adjust the _________ so that the rel stops when the feed stops.
Spool drag
______ systems interlock the power supply and wire feeder.
Synergic
Mixtures of argon with less than ____ percent carbon dioxide may not have enough arc voltage to give desired results.
Ten
Which of the following is true of GMA spot welding?
The burning back of the thin material allows the thicker metal to be melted.
Which of the following is true of pull-type feed systems?
The gun is heavier and more difficult to use
Which of the following is true of mill scale?
The porosity it causes is most often confined to the interior of the weld.
Which of the following is true of axial spray metal transfer?
There are hundreds of drops per second crossing from the wire to the base metal
The axial spray metal transfer process rewuires a current level above a critical amount, called the ______ current.
Transition
GMA spot welding is an excellent process for auto body repair
True
In semiautomatic or automatic processes, the welder is required to work harder because of the greater demands on travel speed and current
True
In the beginning, the GMAW process was used to weld aluminum using argon gas for shielding
True
More amperage is required to melt the wire the faster it is fed
True
The thin copper coating on a steel wire electrode either burns off or is diluted into the weld pool with no significant effect to the weld bead.
True
Wire should not be discarded on the floor because it can work its way into a filter screen on the welding power source
True
Globular transfer occurs at a rate of ____ drops per second.
a few
To prevent the loss of certain alloying elements, ________.
add a deoxidizer to the filler wire.
GMAW is relatively free from spatter because it uses a mode of metal transfer called ________ metal transfer
axial spray
Because of the constant-potential power supply, the welding current will change as the distance between the _________ and the work changes
contact tube
As the electrode extension is shortened, the welding current _____.
decreases
Filler metals and fluxes usually have ______ added to them so that the adverse effects of the mill scale are reduced or eliminated.
deoxidizers
The _______ is the distance from the contact tube to the arc measured along the wire.
electrode extension
The longer the ______, the greater the _____ to the welding current.
electrode extension, resistance
The purpose of the _____ is to provide a steady and reliable supply of wire to the weld
electrode feed unit
The ______ refers to the angle between the GMA welding gun and the work as it relates to the direction of travel.
gun angle
In the pulsed-arc metal transfer current cycle, _____ is the peak current that flows across the arc during the high current pulse
high pulse current
Often, FCAW and SAW will have a ______ amperage range than GMAW.
higher
The _____ the density of a gas, the _____ will be flow rate required for equal arc protection.
lower, higher
At any one voltage setting, _____ amperage is required to melt the wire the _____ it is fed
more, faster
The relationships between current and voltage with different combinations of arc length or wire-feed speeds are called ______ characteristics.
volt-amperage
High gas flow rates ______.
waste shielding gases
Slight changes in ____ can be used to control the weld as the groove spacing changes.
welding gun angle
The ________ rate, measured in inches per minute or pounds per hour, is the rate at which the arc consumes the wire
wire melting