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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. List the three methods of metal transfer with 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
Short- circuiting transfer - Globular transfer - Spray transfer
The time rate of response for the current rise and fall
DCEP (Direct Current Electrode Positive) Reverse Polarity

2. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
The negative side of a welding unit
The time rate of response for the current rise and fall
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
SMAW - GTAW
If you dont know this check your phone
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)

4. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
Generally not as accurate
Reducing the gas source pressure to a constant working pressure

5. What is another term for electrode holders for GMAW?
Guns
By there current carrying capacity
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)

6. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)

7. List 3 wire drive systems and give a short description of each
Dry ice can form within the flow control openings and cause blockage of 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
Wire feed speed
Controls the rate of flow of a shielding gas to the gun nozzle

8. What does voltage do in an electrical circuit?
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow

9. What is the main purpose of 'slope'?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder

10. List several industries that would use GMAW
Shielding the molten weld metal from atmospheric contamination
85%
Pressure vessels and the piping industry
Constant current (CC)

11. What current and polarity is generally used with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)

12. What is a solenoid valve and what actuates it?
Puddle fluidity
...
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. What effect does increasing and decreasing the inductance have on the weld?
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 time rate of response for the current rise and fall
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding process that joins metals by heating them with an electric arc

14. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
20 to 200 times per second
National Electrical Manufactures Association
Puddle fluidity

15. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gives arc voltage values to the control system of the feeder

16. In the GMAW process what does amperage control?
Constant current (CC)
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

17. What type of power source is commonly used with a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Controls the rate of flow of a shielding gas to the gun nozzle
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

18. Give a description of 'pinch effect'
Guns
3
20 to 200 times per second
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

19. What wire are knurled drive rolls most commonly used on?
Minimum distortion due to low heat input
Guns
These terms are quite restrictive and often technically incorrect
Flux cored wires

20. What power sources are used with the GMAW Process?
Pressure vessels and the piping industry
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer

21. What does the term GMAW identify?
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding
Puddle fluidity

22. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
National Electrical Manufactures Association

23. Why must CO2 cylinders be used in the vertical position?
V groove or U groove
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent drawing of liquid CO2 (Carbon Dioxide)

24. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry

25. List the basic equipment requirements for the GMAW process
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination

26. What does inductance control?
Voltage is the force that overcomes resistance to allow amperage flow
The time rate of response for the current rise and fall
Gas metal arc welding
Higher 26 to 35 arc volts

27. What is the purpose of a regulator and what does it indicate on its gauges?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity
3

28. A pull type drive system is usually used on what type of material?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
National Electrical Manufactures Association
Aluminum wire

29. What does a flowmeter do and what does it measure?
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry

30. What is an advantage of pulsed arc transfer with GMAW?
Duty cycle
Pressure - The rate of flow of a shielding gas
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

31. What would be an indication that the drive roll pressure is adjusted correctly?
Spatter problems and poor weld appearance
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity

32. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Pressure vessels and the piping industry
5.8 to 12.5 L/min
Guns

33. In the GMAW process what does voltage control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%
Shielding the molten weld metal from atmospheric contamination
Puddle fluidity

34. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Guns
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination

35. When is the metal transferred with short circuit transfer?
National Electrical Manufactures Association
5.8 to 12.5 L/min
Constant voltage (CV)
When the filler wire is in direct contract with the base metal

36. Why is a line heater required when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Dry ice can form within the flow control openings and cause blockage of shielding gas
1/4 inch to 1/2 inch
Controls the rate of flow of a shielding gas to the gun nozzle

37. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
...
The Arc voltage

38. How many times per second does short circuiting take place?
85%
20 to 200 times per second
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination

39. What is the disadvantage of the gauge preset type of regulator/flowmeter?
National Electrical Manufactures Association
Wire feed speed
85%
Generally not as accurate

40. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
The Arc voltage
12 to 22 arc volts
Minutes of elapsed time continually run (out of 10 minutes)

41. What does the wire feeder control?
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Spatter problems and poor weld appearance
Speed of the feed motor and - starting / stopping electrode feed

42. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Wire feed speed
Higher 26 to 35 arc volts
Gives arc voltage values to the control system of the feeder

43. What controls the wire speed on a voltage sensing wire feeder?
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
Constant current (CC)
The Arc voltage

44. List the factors that determine the mode of metal transfer
Generally not as accurate
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle

45. What is the preferred drive roll design for solid wires?
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle
Gives arc voltage values to the control system of the feeder

46. What is the required arc voltage used for short circuit transfer?
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
12 to 22 arc volts
85%

47. Why is globular transfer generally avoided with GMAW?
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Spatter problems and poor weld appearance
Gas metal arc welding

48. What 2 controls are found on a GMAW set- up?
Flux cored wires
Wire feed speed - Voltage control
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

49. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding
85%
Penetration and burn - off rate of the electrode

50. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Wire feed speed - Voltage control
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal