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. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The time rate of response for the current rise and fall
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
3

2. What does inductance control?
The time rate of response for the current rise and fall
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
15 feet (4.5 meters)
To prevent drawing of liquid CO2 (Carbon Dioxide)

3. What happens when the electrode extension is increased?
Cause flaking - which can clog the liner and contact tube
The resistace to electrical current flow increases with it. Causing the electrode to heat
Shielding the molten weld metal from atmospheric contamination
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

4. What is the purpose of a regulator and what does it indicate on its gauges?
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
Flux cored wires
SMAW - GTAW

5. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Insufficient current to melt the wire off cleanly
12 to 22 arc volts
85%

6. What does the term GMAW identify?
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
These terms are quite restrictive and often technically incorrect
(DCEP) Direct Current Electrode Positive or Reverse polarity

7. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
Wire feed speed - Voltage control
Duty cycle

8. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Wire feed speed
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
The resistace to electrical current flow increases with it. Causing the electrode to heat

9. What 2 organizations designate specifications for GMAW wires?
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
AWS and CSA
5.8 to 12.5 L/min

10. What would be an indication that the drive roll pressure is adjusted correctly?
The negative side of a welding unit
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle

11. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
The Arc voltage
20 to 200 times per second
Puddle fluidity
85%

12. What current and polarity is generally used with GMAW?
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure - The rate of flow of a shielding gas

13. What is a typical flow rate of CO2 for short circuit transfer?
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min

14. What output on the welding machine is used to rate the duty cycle?
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance
Guns
Minutes of elapsed time continually run (out of 10 minutes)

15. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To limit the short circuiting current so that spatter is reduced
Minutes of elapsed time continually run (out of 10 minutes)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

16. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly
3
If you dont know this check your phone

17. List several industries that would use GMAW
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3

18. When is the metal transferred with short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity
When the filler wire is in direct contract with the base metal
15 feet (4.5 meters)

19. Why is a line heater required when using GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas

20. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Penetration and burn - off rate of the electrode
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)

21. What wire are knurled drive rolls most commonly used on?
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed
Flux cored wires
Wire feeds smoothly (yet will slip should a problem occur in the gun)

22. Give a description of 'pinch effect'
Puddle fluidity
DCEP (Direct Current Electrode Positive) Reverse Polarity
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

23. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Constant voltage (CV)

24. What is the main purpose of 'slope'?
...
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
V groove or U groove

25. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone
5.8 to 12.5 L/min

26. What does the abbreviation NEMA stand for?
The Arc voltage
Constant current (CC)
1/4 inch to 1/2 inch
National Electrical Manufactures Association

27. What type of power source is commonly used with a voltage sensing wire feeder?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed
These terms are quite restrictive and often technically incorrect
Constant current (CC)

28. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity
V groove or U groove

29. What does the wire feeder control?
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input

30. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
15 feet (4.5 meters)
5.8 to 12.5 L/min

31. Give a brief description of the GMAW process
3
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone
Flux cored wires

32. What 2 controls are found on a GMAW set- up?
Duty cycle
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Flux cored wires
Puddle fluidity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
...

34. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Constant voltage (CV)
Higher 26 to 35 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)

35. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or 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

36. Draw a typical volt amp curve for a machine that is designed for GMAW
Minimum distortion due to low heat input
If you dont know this check your phone
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle

37. What type of power source is used with a constant speed wire feeder?
Gives arc voltage values to the control system of the feeder
3
Constant voltage (CV)
Duty cycle

38. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
5.8 to 12.5 L/min
Higher 26 to 35 arc volts
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas

39. List 3 wire drive systems and give a short description of each
The negative side of a welding unit
(DCEP) Direct Current Electrode Positive or 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
20 to 200 times per second

40. A 10 minute cycle of welding time vs cooling time a given machine can handle.
85%
1/4 inch to 1/2 inch
Guns
Duty cycle

41. How are GMAW guns rated?
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity
20 to 200 times per second
Duty cycle

42. List the basic equipment requirements for the GMAW process
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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
When the filler wire is in direct contract with the base metal

43. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas

44. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit

45. Regulators control_____________ flowmeters SHOW____________.
The time rate of response for the current rise and fall
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed

46. What controls amperage when using GMAW?
Wire feed speed
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
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. Why is the term GMAW preferred over MIG or MAG?
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect

48. In the GMAW process what does amperage control?
Higher 26 to 35 arc volts
Penetration and burn - off rate of the electrode
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)

49. What is an advantage of pulsed arc transfer with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
The Arc voltage
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

50. Why is globular transfer generally avoided with GMAW?
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance
Constant current (CC)
Welding process that joins metals by heating them with an electric arc