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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 a typical flow rate of CO2 for short circuit transfer?
Penetration and burn - off rate of the electrode
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min

2. List several industries that would use GMAW
Pressure vessels and the piping industry
Flux cored wires
Constant current (CC)
5.8 to 12.5 L/min

3. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input

4. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
AWS and CSA
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
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6. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant- speed wire feeders and Voltage- sennsing wire feeders
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas

7. What type of power source is commonly used with a voltage sensing wire feeder?
Aluminum wire
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)
Constant voltage (CV)

8. What does voltage do in an electrical circuit?
20 to 200 times per second
Voltage is the force that overcomes resistance to allow amperage flow
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced

9. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
(DCEP) Direct Current Electrode Positive or Reverse polarity
Guns
Cause flaking - which can clog the liner and contact tube

10. Why must CO2 cylinders be used in the vertical position?
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)
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11. What is the key advantage of short circuiting transfer?
These terms are quite restrictive and often technically incorrect
Wire feed speed
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat

12. What is the disadvantage of the gauge preset type of regulator/flowmeter?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Generally not as accurate

13. What is another term for electrode holders for GMAW?
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Guns
V groove or U groove

14. What does the term GMAW identify?
The negative side of a welding unit
Gas metal arc welding
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity

15. What does the abbreviation NEMA stand for?
Minimum distortion due to low heat input
Gas metal arc welding
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National Electrical Manufactures Association

16. What is the required arc voltage used for short circuit transfer?
Aluminum wire
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)

17. Regulators control_____________ flowmeters SHOW____________.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure - The rate of flow of a shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%

18. Give a description of 'pinch effect'
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Aluminum wire

19. In the GMAW process what does amperage control?
When the filler wire is in direct contract with the base metal
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode

20. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
Aluminum wire
Constant- speed wire feeders and Voltage- sennsing wire feeders
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

21. Why is the term GMAW preferred over MIG or MAG?
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
Guns

22. Why is a line heater required when using GMAW?
AWS and CSA
5.8 to 12.5 L/min
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

23. What power sources are used with the GMAW Process?
Pressure - The rate of flow of a shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
When the filler wire is in direct contract with the base metal
Generally not as accurate

24. 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
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure
Gas metal arc welding

25. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Insufficient current to melt the wire off cleanly
3

26. 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
20 to 200 times per second
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)

27. List the factors that determine the mode of metal transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer

28. What type of power source is used with a constant speed wire feeder?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

29. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
Penetration and burn - off rate of the electrode

30. List the basic equipment requirements for the GMAW process
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance

31. When is the metal transferred with short circuit transfer?
If you dont know this check your phone
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
Duty cycle

32. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
20 to 200 times per second

33. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
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
20 to 200 times per second

34. Why is globular transfer generally avoided with GMAW?
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance
V groove or U groove

35. In the GMAW process what does voltage control?
Duty cycle
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode
Puddle fluidity

36. How many times per second does short circuiting take place?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch

37. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination
12 to 22 arc volts
Puddle fluidity

38. With straight polarity where is 2/3 of the arc energy?
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The negative side of a welding unit

39. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode

40. What output on the welding machine is used to rate the duty cycle?
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)

41. What does a flowmeter do and what does it measure?
Minimum distortion due to low heat input
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage
These terms are quite restrictive and often technically incorrect

42. List the three methods of metal transfer with GMAW
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube

43. What wire are knurled drive rolls most commonly used on?
The Arc voltage
To prevent drawing of liquid CO2 (Carbon Dioxide)
20 to 200 times per second
Flux cored wires

44. What is the recommended electrode stick- out for .035 solid wire?
V groove or U groove
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch

45. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
Guns
Higher 26 to 35 arc volts

46. List 3 forms compressed gases may be supplied for welding
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The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)

47. What 2 controls are found on a GMAW set- up?
Generally not as accurate
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control

48. What is a solenoid valve and what actuates it?
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

49. How are GMAW guns rated?
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas

50. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Higher 26 to 35 arc volts