Gas Metal Arc Welding

Instructions:

• Answer 50 questions in 15 minutes.
• If you are not ready to take this test, you can study here.
• Match each statement with the correct term.
• Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
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Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
85%


2. Why is the term GMAW preferred over MIG or MAG?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Guns
Puddle fluidity
These terms are quite restrictive and often technically incorrect


3. When is the metal transferred with short circuit transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
1/4 inch to 1/2 inch


4. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
The time rate of response for the current rise and fall
Duty cycle
Higher 26 to 35 arc volts


5. What does the term GMAW identify?
Penetration and burn - off rate of the electrode
Wire feed speed
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer


6. Why is a fiber washer required and what cylinder gas requires it?
Reducing the gas source pressure to a constant working pressure
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed
Minimum distortion due to low heat input


7. What is the maximum distance that hard wire can be successfully pushed?
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Penetration and burn - off rate of the electrode
20 to 200 times per second
15 feet (4.5 meters)


8. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
These terms are quite restrictive and often technically incorrect
...
Insufficient current to melt the wire off cleanly
5.8 to 12.5 L/min


9. What is another term for electrode holders for GMAW?
12 to 22 arc volts
3
Constant current (CC)
Guns


10. What would be an indication that the drive roll pressure is adjusted correctly?
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)


11. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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15 feet (4.5 meters)
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs


12. What controls the wire speed on a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)
The Arc voltage
To limit the short circuiting current so that spatter is reduced


13. What controls amperage when using GMAW?
These terms are quite restrictive and often technically incorrect
Aluminum wire
Wire feed speed
Constant voltage (CV)


14. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs
85%


15. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Wire feed speed - Voltage control
Generally not as accurate


16. Why must CO2 cylinders be used in the vertical position?
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
Wire feed speed


17. What is the preferred drive roll design for solid wires?
Constant voltage (CV)
Pressure vessels and the piping industry
85%
V groove or U groove


18. What effect does increasing and decreasing the inductance have on the weld?
V groove or U groove
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts


19. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Minimum distortion due to low heat input
The negative side of a welding unit
Minutes of elapsed time continually run (out of 10 minutes)
(DCEP) Direct Current Electrode Positive or Reverse polarity


20. What 2 controls are found on a GMAW set- up?
15 feet (4.5 meters)
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Shielding the molten weld metal from atmospheric contamination


21. What does the wire feeder control?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed


22. Why is globular transfer generally avoided with GMAW?
Minimum distortion due to low heat input
Gas metal arc welding
Spatter problems and poor weld appearance
Short- circuiting transfer - Globular transfer - Spray transfer


23. How many times per second does short circuiting take place?
Higher 26 to 35 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
Constant voltage (CV)


24. What wire are knurled drive rolls most commonly used on?
Flux cored wires
...
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5.8 to 12.5 L/min


25. List several industries that would use GMAW
3
Wire feed speed - Voltage control
V groove or U groove
Pressure vessels and the piping industry


26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Penetration and burn - off rate of the electrode
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure - The rate of flow of a shielding gas


27. A pull type drive system is usually used on what type of material?
Aluminum wire
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity
Controls the rate of flow of a shielding gas to the gun nozzle


28. What 2 organizations designate specifications for GMAW wires?
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
5.8 to 12.5 L/min


29. What is the key advantage of short circuiting transfer?
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity


30. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs


31. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
Cause flaking - which can clog the liner and contact tube


32. What is the effect of too much slope?
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Insufficient current to melt the wire off cleanly
SMAW - GTAW


33. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)


34. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas
Speed of the feed motor and - starting / stopping electrode feed
Cause flaking - which can clog the liner and contact tube


35. What is the main purpose of 'slope'?
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed
To limit the short circuiting current so that spatter is reduced


36. What is the required arc voltage used for short circuit transfer?
5.8 to 12.5 L/min
12 to 22 arc volts
The negative side of a welding unit
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun


37. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity


38. How are GMAW guns rated?
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
15 feet (4.5 meters)


39. What is a solenoid valve and what actuates it?
When the filler wire is in direct contract with the base metal
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry
AWS and CSA


40. What happens when the electrode extension is increased?
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire


41. What does the abbreviation NEMA stand for?
Pressure vessels and the piping industry
AWS and CSA
National Electrical Manufactures Association
12 to 22 arc volts


42. List the three methods of metal transfer with GMAW
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer


43. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination
Gives arc voltage values to the control system of the feeder
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze


44. What current and polarity is generally used with GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
DCEP (Direct Current Electrode Positive) Reverse Polarity


45. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld


46. Draw a typical volt amp curve for a machine that is designed for GMAW
To limit the short circuiting current so that spatter is reduced
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun


47. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
Gas metal arc welding


48. What does inductance control?
The time rate of response for the current rise and fall
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)
Reducing the gas source pressure to a constant working pressure


49. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
3


50. What power sources are used with the GMAW Process?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs