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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. List 3 wire drive systems and give a short description of each
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed
Constant voltage (CV)
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

2. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
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3. When is the metal transferred with short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Penetration and burn - off rate of the electrode
V groove or U groove
When the filler wire is in direct contract with the base metal

4. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association

5. What does inductance control?
5.8 to 12.5 L/min
Controls the rate of flow of a shielding gas to the gun nozzle
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

6. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
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7. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
12 to 22 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min

8. Why is the term GMAW preferred over MIG or MAG?
The negative side of a welding unit
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc

9. What is another term for electrode holders for GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
Guns
Penetration and burn - off rate of the electrode

10. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
The negative side of a welding unit
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

11. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity
Reducing the gas source pressure to a constant working pressure
Controls the rate of flow of a shielding gas to the gun nozzle

12. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Aluminum wire
85%
Constant voltage (CV)
5.8 to 12.5 L/min

13. Why must CO2 cylinders be used in the vertical position?
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
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)

14. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
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15. What is a solenoid valve and what actuates it?
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

16. Draw a typical volt amp curve for a machine that is designed for GMAW
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Constant current (CC)
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

17. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
12 to 22 arc volts
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity

18. How are GMAW guns rated?
Puddle fluidity
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

19. Give a brief description of the GMAW process
V groove or U groove
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc

20. What output on the welding machine is used to rate the duty cycle?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer

21. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Gives arc voltage values to the control system of the feeder
Speed of the feed motor and - starting / stopping electrode feed
The time rate of response for the current rise and fall
Higher 26 to 35 arc volts

22. In the GMAW process what does amperage control?
Reducing the gas source pressure to a constant working pressure
20 to 200 times per second
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas

23. What is the effect of too much slope?
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
Wire feed speed

24. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
The Arc voltage

25. What are the 2 types of wire feeders available?
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant voltage (CV)

26. What happens when the electrode extension is increased?
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)

27. What is a typical flow rate of CO2 for short circuit transfer?
Wire feed speed - Voltage control
5.8 to 12.5 L/min
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity

28. What does the term GMAW identify?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The time rate of response for the current rise and fall
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gas metal arc welding

29. In the GMAW process what does voltage control?
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity
3

30. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Cause flaking - which can clog the liner and contact tube
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...
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

31. What effect does increasing and decreasing the inductance have on the weld?
AWS and CSA
Pressure vessels and the piping industry
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
12 to 22 arc volts

32. What is the main purpose of 'slope'?
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
Duty cycle
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts

33. What current and polarity is generally used with GMAW?
Pressure vessels and the piping industry
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DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage

34. Give a description of 'pinch effect'
Puddle fluidity
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
Minimum distortion due to low heat input

35. List several industries that would use GMAW
National Electrical Manufactures Association
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Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas

36. List the three methods of metal transfer with GMAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly

37. With straight polarity where is 2/3 of the arc energy?
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
The negative side of a welding unit
Penetration and burn - off rate of the electrode

38. What is the preferred drive roll design for solid wires?
5.8 to 12.5 L/min
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

39. What type of power source is commonly used with a voltage sensing wire feeder?
The negative side of a welding unit
Constant current (CC)
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube

40. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
3
Spatter problems and poor weld appearance
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Gas metal arc welding

41. What wire are knurled drive rolls most commonly used on?
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Flux cored wires
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

42. Why is a line heater required when using GMAW?
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW

43. What does a flowmeter do and what does it measure?
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
Controls the rate of flow of a shielding gas to the gun nozzle
SMAW - GTAW

44. How many times per second does short circuiting take place?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second

45. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

46. What does voltage do in an electrical circuit?
By there current carrying capacity
SMAW - GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow

47. What 2 organizations designate specifications for GMAW wires?
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
AWS and CSA
1/4 inch to 1/2 inch

48. Why is a fiber washer required and what cylinder gas requires it?
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts

49. A pull type drive system is usually used on what type of material?
Constant voltage (CV)
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire

50. Regulators control_____________ flowmeters SHOW____________.
Duty cycle
Pressure - The rate of flow of a shielding gas
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Constant voltage (CV)