Deck 10: Gas Metal Arc Welding Equipment, Setup, and Operation

Question 1

When the GMAW-S process is properly tuned, what is the approximate rate of its cycling?

A) Overshoot
B) Ramp up
C) High pulse current
D) 20 to 200 times per second

Answer 1

D

Question 2

MAG is short for ____.

A) metal arc gas welding
B) metal active gas welding
C) metal action gas welding
D) metal anion gas welding

Answer 2

B

Question 3

The purpose of the ____ is to provide a steady and reliable supply of wire to the weld.

A) power source
B) electrode feeder
C) electrode conduit
D) welding gun

Answer 3

B

Question 4

The shielding gas used on carbon steel is ____.

A) helium
B) carbon dioxide, or a mixture of carbon dioxide and argon
C) argon
D) argon, or a mixture of argon and helium

Question 5

Which of the following is true of globular transfer?

A) It is used more commonly in combination with pulsed-spray transfer.
B) The arc's real work occurs when the current pulses above the transition current.
C) There are hundreds of drops per second crossing from the wire to the base metal.
D) The process requires a current level above the transition current.

Question 6

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.

A) 10% oxygen
B) 20% nitrogen
C) 50% carbon dioxide
D) 80% helium

Question 7

In the pulsed-arc metal transfer current cycle, ____ refers to the surging electrical current passing through the transformer like a wave on water.

A) overshoot
B) ramp up
C) high pulse current
D) pulse width

Question 8

In the pulsed-arc metal transfer current cycle, ____ is the peak current that flows across the arc during the high current pulse.

A) ramp up
B) high pulse current
C) high current time
D) step-off current

Question 9

____ is a series of ridges cut into the groove.

A) Ridging
B) Smoothing
C) Knurling
D) V-grooving

Question 10

GMA welding machines have ____ duty cycle.

A) 20 percent
B) 60 percent
C) 80 percent
D) 100 percent

Question 11

Which of the following is true of perpendicular welding technique?

A) It has a good balance between penetration and reinforcement and is used on automated welding.
B) It has good bead visibility and makes welds with deeper joint penetration.
C) It has good joint visibility and makes welds with less joint penetration.
D) It works well on vertical up and overhead welds.

Question 12

What changes to the welding machine are required to change between short-circuiting and axial spray or between axial spray and buried arc transfer methods?

A) Change the shielding gas from Ar to 100% CO₂or He to Ar+O₂.
B) Make the changes in the welding machine's voltage and amperage settings.
C) Increase the voltage.
D) Increase the amperage.

Question 13

In the ____ feed system, the electrode must have enough strength to be pushed through the conduit without kinking.

A) push-type
B) pull-type
C) push-pull-type
D) linear

Question 14

In axial spray metal transfer, the shielding gas is usually a mixture of ____.

A) 95% to 98% argon and 2% to 5% oxygen
B) 2% to 5% argon and 95% to 98% oxygen
C) 50% argon and 50% oxygen
D) 5% argon and 95% oxygen

Question 15

Why would a welder need extra burn protection for their eyes when making an axial spray weld?

A) To protect the eye from the increased weld spatter.
B) To protect the eye from the increased heat produced by axial spray arc welding.
C) The high welding current produces a great deal of UV light.
D) The hot metal can cause infrared light burns to the eye and face.

Question 16

Which of the following is true of axial spray transfers using high current settings?

A) Higher currents are needed with smaller diameter wires.
B) High current aids welding sheet metal because the high heat cuts through sheet metal.
C) High current settings may cause the weld to be difficult to control in out-of-position welds.
D) The need for higher current removes some restrictions on the process.

Question 17

Which of the following is true of GMA spot welding?

A) Welds can only be made in thin materials.
B) The weld cannot be made if only one side of the materials to be welded is accessible.
C) The weld cannot be made when there is paint on the interfacing surfaces.
D) The burning back of the thin material allows the thicker metal to be melted.

Question 18

The GMAW-S process does not produce enough heat to make quality welds in sections much thicker than ______________ unless it is used for the root pass on a grooved weld or to fill gaps in joints.

A) 1/2 in. (13 mm)
B) 5/16in. (8 mm)
C) 1/4 in. (6 mm)
D) 1/8 in. (3 mm)

Question 19

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.

A) step-off current
B) high current time
C) ramp up
D) ramp down

Question 20

What gas is added to argon for the axial spray transfer method transfer?

A) O₂(Oxygen)
B) CO₂(Carbon dioxide)
C) He (Helium)
D) N (Nitrogen)

Question 21

In modulated current metal transfer the wire feed speed is _____________.

Question 22

Changes in the step-off current have been associated with arc stability________________.

A) to make vertical up and overhead welds
B) when only AC power is available for the welding current
C) on aluminum and copper alloys
D) for some higher electrically resistant filler metals such as stainless steel and nickel alloys

Question 23

The ____________________ is the distance from the contact tube to the arc measured along the wire.

Question 24

The ____________________ rate, measured in inches per minute or pounds per hour, is the rate at which the arc consumes the wire.

Question 25

Explain how to measure the wire-feed ipm.

Question 26

The modulated current transfer process can be used to make code quality root welds ______.

A) only if the root face is 1/8 in (3 mm) and the root opening is 7/32 in. (2.7 mm)
B) when the root face is twice the size of the root opening but less than 5/32 in (4 mm)
C) even if the root opening and root face may vary as much as the code might allow
D) only in ferrous (steel) alloys

Question 27

The ____________________ rate is the measure of the weld metal deposited.

Question 28

Explain the modulated current metal transfer process.

Question 29

GMAW-P welds made on most metals other than steel use __________shielding gas.

A) 2% oxygen + 98% argon
B) 100% argon
C) 25% helium + 75% argon
D) 25%CO₂+ 75% argon

Question 30

GMAW-P is a ____________________ system that interlocks the power supply and wire feeder.

Question 31

Explain why the power supply is critical in the short-circuiting transfer process.

Question 32

Explain why the use of GMA welding can help reduce waste of filler metals.

Question 33

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.

A) pulse width
B) ramp down
C) ramp up
D) overshoot

Question 34

The ________ current of the spray mode produces good penetration and fusion, and the ____ current allows the weld pool to cool and contract slightly.

A) DCEN, DCEP
B) DCEP, DCEN
C) AC DCEP
D) high, low

Question 35

GMAW power supplies are ____ type machines.

A) constant-current and constant-voltage
B) constant-voltage and constant-potential
C) drooping arc voltage and constant-current
D) constant-current and constant-potential

Question 36

The relationships between current and voltage with different combinations of arc length or wire-feed speeds are called ____________________ characteristics.

Question 37

The _____________ wire feed system has the advantage of being enclosed in a case.

Question 38

Modulated current metal transfer uses an extremely modified version of _________.

Question 39

GMAW is almost free from spatter because it uses a mode of metal transfer called ____________________ metal transfer.

Question 40

The rate of voltage decrease as the amperage increases within the working range is known as ____________________.