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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 purpose of a regulator and what does it indicate on its gauges?
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure

2. What effect does increasing and decreasing the inductance have on the weld?
Higher 26 to 35 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To limit the short circuiting current so that spatter is reduced
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

3. What output on the welding machine is used to rate the duty cycle?
Guns
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

4. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Aluminum wire
Welding process that joins metals by heating them with an electric arc
These terms are quite restrictive and often technically incorrect

5. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
1/4 inch to 1/2 inch
...

6. Give a brief description of the GMAW process
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed

7. Why is the term GMAW preferred over MIG or MAG?
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination
85%

8. What is the purpose of the shielding gas used in GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination
The Arc voltage

9. Why is a fiber washer required and what cylinder gas requires it?
National Electrical Manufactures Association
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent leakage - Carbon Dioxide (CO2)

10. What is the recommended electrode stick- out for .035 solid wire?
Duty cycle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
1/4 inch to 1/2 inch
Wire feed speed

11. How many times per second does short circuiting take place?
12 to 22 arc volts
National Electrical Manufactures Association
Spatter problems and poor weld appearance
20 to 200 times per second

12. In the GMAW process what does amperage control?
The time rate of response for the current rise and fall
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gives arc voltage values to the control system of the feeder
Penetration and burn - off rate of the electrode

13. What is an advantage of pulsed arc transfer with GMAW?
When the filler wire is in direct contract with the base metal
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

14. What is the main purpose of 'slope'?
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect

15. List 3 forms compressed gases may be supplied for welding
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed
Penetration and burn - off rate of the electrode

16. What does a flowmeter do and what does it measure?
Constant voltage (CV)
Constant current (CC)
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feeds smoothly (yet will slip should a problem occur in the gun)

17. What is the key advantage of short circuiting transfer?
National Electrical Manufactures Association
Minimum distortion due to low heat input
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow

18. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity

19. List 3 wire drive systems and give a short description of each
Gas metal arc welding
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

20. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)

21. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)

22. What is the required arc voltage used for short circuit transfer?
If you dont know this check your phone
12 to 22 arc volts
15 feet (4.5 meters)
To limit the short circuiting current so that spatter is reduced

23. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Reducing the gas source pressure to a constant working pressure
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

24. What would be an indication that the drive roll pressure is adjusted correctly?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
Puddle fluidity
Wire feeds smoothly (yet will slip should a problem occur in the gun)

25. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant current (CC)
Duty cycle
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas

26. List the three methods of metal transfer with GMAW
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas
Short- circuiting transfer - Globular transfer - Spray transfer
Voltage is the force that overcomes resistance to allow amperage flow

27. What type of power source is used with a constant speed wire feeder?
3
1/4 inch to 1/2 inch
Generally not as accurate
Constant voltage (CV)

28. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To limit the short circuiting current so that spatter is reduced
(DCEP) Direct Current Electrode Positive or Reverse polarity

29. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)

30. What current and polarity is generally used with GMAW?
15 feet (4.5 meters)
Puddle fluidity
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

31. A pull type drive system is usually used on what type of material?
Constant current (CC)
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

32. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
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
Speed of the feed motor and - starting / stopping electrode feed

33. What is the maximum distance that hard wire can be successfully pushed?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow

34. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Controls the rate of flow of a shielding gas to the gun nozzle
85%
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

35. In the GMAW process what does voltage control?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

36. What wire are knurled drive rolls most commonly used on?
National Electrical Manufactures Association
The time rate of response for the current rise and fall
1/4 inch to 1/2 inch
Flux cored wires

37. Why must CO2 cylinders be used in the vertical position?
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder
By there current carrying capacity

38. What does inductance control?
To prevent leakage - Carbon Dioxide (CO2)
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall

39. List the basic equipment requirements for the GMAW process
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Cause flaking - which can clog the liner and contact tube

40. Draw a typical volt amp curve for a machine that is designed for GMAW
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts
Duty cycle
If you dont know this check your phone

41. When is the metal transferred with short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect

42. What is a solenoid valve and what actuates it?
Reducing the gas source pressure to a constant working pressure
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
3

43. What is the effect of too much slope?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect

44. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall
Gas metal arc welding
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

45. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure

46. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Constant voltage (CV)
20 to 200 times per second
V groove or U groove

47. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant voltage (CV)
Pressure - The rate of flow of a shielding gas
85%
By there current carrying capacity

48. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Wire feed speed
National Electrical Manufactures Association

49. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall
SMAW - GTAW

50. What 2 controls are found on a GMAW set- up?
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association
Wire feed speed - Voltage control
Pressure vessels and the piping industry