Test your basic knowledge |

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. What is the required arc voltage used for short circuit transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
12 to 22 arc volts
National Electrical Manufactures Association
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

2. What is the main purpose of 'slope'?
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

3. What wire are knurled drive rolls most commonly used on?
Flux cored wires
15 feet (4.5 meters)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To limit the short circuiting current so that spatter is reduced

4. Give a brief description of the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc

5. When is the metal transferred with short circuit transfer?
15 feet (4.5 meters)
When the filler wire is in direct contract with the base metal
Gas metal arc welding
Pressure - The rate of flow of a shielding gas

6. What is the key advantage of short circuiting transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
3

7. Why is a fiber washer required and what cylinder gas requires it?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Reducing the gas source pressure to a constant working pressure
To prevent leakage - Carbon Dioxide (CO2)
Push type: Wire is fed by a set of drive rolls located in the wire feed unit - Pull type: Drive rolls mounted in the gun itself - Push- pull type: Combination of the two

8. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Welding process that joins metals by heating them with an electric arc
...
To limit the short circuiting current so that spatter is reduced
SMAW - GTAW

9. What type of power source is commonly used with a voltage sensing wire feeder?
The resistace to electrical current flow increases with it. Causing the electrode to heat
The time rate of response for the current rise and fall
Push type: Wire is fed by a set of drive rolls located in the wire feed unit - Pull type: Drive rolls mounted in the gun itself - Push- pull type: Combination of the two
Constant current (CC)

10. What is the purpose of the shielding gas used in GMAW?
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
National Electrical Manufactures Association

11. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Puddle fluidity
85%
Duty cycle

12. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
...
V groove or U groove

13. What does a flowmeter do and what does it measure?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
Constant current (CC)

14. List the three methods of metal transfer with GMAW
Reducing the gas source pressure to a constant working pressure
Controls the rate of flow of a shielding gas to the gun nozzle
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer

15. What does the abbreviation NEMA stand for?
To limit the short circuiting current so that spatter is reduced
...
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle

16. How many times per second does short circuiting take place?
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode
By there current carrying capacity
20 to 200 times per second

17. In the GMAW process what does voltage control?
To prevent leakage - Carbon Dioxide (CO2)
Puddle fluidity
When the filler wire is in direct contract with the base metal
Duty cycle

18. Why is a line heater required when using GMAW?
12 to 22 arc volts
Gas metal arc welding
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association

19. List the basic equipment requirements for the GMAW process
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry
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

20. What is a solenoid valve and what actuates it?
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination

21. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Guns

22. A pull type drive system is usually used on what type of material?
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Aluminum wire
If you dont know this check your phone

23. What 2 controls are found on a GMAW set- up?
...
Puddle fluidity
Gas metal arc welding
Wire feed speed - Voltage control

24. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Duty cycle

25. What processes are constant current (CC) power sources designed to be used with?
Controls the rate of flow of a shielding gas to the gun nozzle
SMAW - GTAW
Gas metal arc welding
If you dont know this check your phone

26. What would be an indication that the drive roll pressure is adjusted correctly?
3
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
5.8 to 12.5 L/min

27. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Cause flaking - which can clog the liner and contact tube

28. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts
Motor driven generators - Transformer rectifiers - and Inverter designs

29. List the factors that determine the mode of metal transfer
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association

30. What does the term GMAW identify?
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch
12 to 22 arc volts

31. What 2 organizations designate specifications for GMAW wires?
...
AWS and CSA
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder

32. What is another term for electrode holders for GMAW?
Constant current (CC)
Aluminum wire
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns

33. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
...
Guns
20 to 200 times per second

34. What output on the welding machine is used to rate the duty cycle?
Constant voltage (CV)
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
Aluminum wire

35. What are the 2 types of wire feeders available?
SMAW - GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

36. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Gas metal arc welding
...
1/4 inch to 1/2 inch

37. What is an advantage of pulsed arc transfer with GMAW?
Constant voltage (CV)
12 to 22 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The resistace to electrical current flow increases with it. Causing the electrode to heat

38. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Reducing the gas source pressure to a constant working pressure
Constant current (CC)
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

39. What controls the wire speed on a voltage sensing wire feeder?
AWS and CSA
Reducing the gas source pressure to a constant working pressure
The Arc voltage
Guns

40. Why is globular transfer generally avoided with GMAW?
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity
85%
Spatter problems and poor weld appearance

41. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA

42. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Generally not as accurate
Constant current (CC)

43. What happens when the electrode extension is increased?
AWS and CSA
Flux cored wires
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. What does the wire feeder control?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)

45. Why must CO2 cylinders be used in the vertical position?
Shielding the molten weld metal from atmospheric contamination
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
(DCEP) Direct Current Electrode Positive or Reverse polarity

46. What current and polarity is generally used with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The Arc voltage
DCEP (Direct Current Electrode Positive) Reverse Polarity
Push type: Wire is fed by a set of drive rolls located in the wire feed unit - Pull type: Drive rolls mounted in the gun itself - Push- pull type: Combination of the two

47. Give a description of 'pinch effect'
(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode
To prevent leakage - Carbon Dioxide (CO2)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

48. Why is the term GMAW preferred over MIG or MAG?
Puddle fluidity
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall

49. Regulators control_____________ flowmeters SHOW____________.
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
SMAW - GTAW
Minimum distortion due to low heat input

50. What type of power source is used with a constant speed wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)