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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
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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 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
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

2. What is the recommended electrode stick- out for .035 solid wire?
The negative side of a welding unit
By there current carrying capacity
1/4 inch to 1/2 inch
Generally not as accurate

3. What type of power source is used with a constant speed wire feeder?
Gives arc voltage values to the control system of the feeder
15 feet (4.5 meters)
Gas metal arc welding
Constant voltage (CV)

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

5. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer
Shielding the molten weld metal from atmospheric contamination

6. What is the required arc voltage used for short circuit transfer?
The negative side of a welding unit
12 to 22 arc volts
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

7. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow

8. Give a brief description of the GMAW process
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc
15 feet (4.5 meters)

9. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
12 to 22 arc volts
Puddle fluidity
20 to 200 times per second

10. What does the term GMAW identify?
Gas metal arc welding
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
V groove or U groove

11. List several industries that would use GMAW
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs

12. What current and polarity is generally used with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts

13. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns
Insufficient current to melt the wire off cleanly

14. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts
These terms are quite restrictive and often technically incorrect
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

15. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
By there current carrying capacity
V groove or U groove
When the filler wire is in direct contract with the base metal

16. In the GMAW process what does voltage control?
Insufficient current to melt the wire off cleanly
Puddle fluidity
Flux cored wires
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

17. What wire are knurled drive rolls most commonly used on?
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)

18. What is an advantage of pulsed arc transfer with GMAW?
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
3
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

19. What is the purpose of a regulator and what does it indicate on its gauges?
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall
Minimum distortion due to low heat input
Reducing the gas source pressure to a constant working pressure

20. What is the maximum distance that hard wire can be successfully pushed?
Generally not as accurate
15 feet (4.5 meters)
By there current carrying capacity
Puddle fluidity

21. What does a flowmeter do and what does it measure?
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
Puddle fluidity
3

22. List the basic equipment requirements for the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity

23. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
12 to 22 arc volts

24. 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
Minimum distortion due to low heat input
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

25. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns
By there current carrying capacity

26. How many times per second does short circuiting take place?
Speed of the feed motor and - starting / stopping electrode feed
Spatter problems and poor weld appearance
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)

27. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall
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

28. Why is a fiber washer required and what cylinder gas requires it?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
Aluminum wire
To prevent leakage - Carbon Dioxide (CO2)

29. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
85%
Higher 26 to 35 arc volts
3

30. What are the 2 types of wire feeders available?
To prevent leakage - Carbon Dioxide (CO2)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant current (CC)

31. How are GMAW guns rated?
Minimum distortion due to low heat input
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

32. What is another term for electrode holders for GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns
If you dont know this check your phone
By there current carrying capacity

33. What is a typical flow rate of CO2 for short circuit transfer?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gives arc voltage values to the control system of the feeder
5.8 to 12.5 L/min
Aluminum wire

34. What is the preferred drive roll design for solid wires?
V groove or U groove
Constant current (CC)
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders

35. What is the effect of too much slope?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Guns
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced

36. List the factors that determine the mode of metal transfer
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer

37. With straight polarity where is 2/3 of the arc energy?
If you dont know this check your phone
3
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)

38. List the three methods of metal transfer with GMAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Short- circuiting transfer - Globular transfer - Spray transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Voltage is the force that overcomes resistance to allow amperage flow

39. What effect does increasing and decreasing the inductance have on the weld?
Voltage is the force that overcomes resistance to allow amperage flow
3
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

40. When is the metal transferred with short circuit transfer?
The time rate of response for the current rise and fall
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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

41. What is the main purpose of 'slope'?
Penetration and burn - off rate of the electrode
To limit the short circuiting current so that spatter is reduced
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow

42. What controls the wire speed on a voltage sensing wire feeder?
Aluminum wire
The Arc voltage
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)

43. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Spatter problems and poor weld appearance

44. Why is globular transfer generally avoided with GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
If you dont know this check your phone
By there current carrying capacity

45. What would be an indication that the drive roll pressure is adjusted correctly?
5.8 to 12.5 L/min
Wire feed speed - Voltage control
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage

46. What does the abbreviation NEMA stand for?
85%
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

47. In the GMAW process what does amperage control?
By there current carrying capacity
Minimum distortion due to low heat input
Penetration and burn - off rate of the electrode
Spatter problems and poor weld appearance

48. What type of power source is commonly used with a voltage sensing wire feeder?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle

49. What does voltage do in an electrical circuit?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow

50. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Aluminum wire
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
Generally not as accurate