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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. Why is the term GMAW preferred over MIG or MAG?
By there current carrying capacity
Aluminum wire
Minimum distortion due to low heat input
These terms are quite restrictive and often technically incorrect

2. What is another term for electrode holders for GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
Guns

3. What controls the wire speed on a voltage sensing wire feeder?
These terms are quite restrictive and often technically incorrect
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
The Arc voltage

4. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
...
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube

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
National Electrical Manufactures Association
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)

6. List 3 wire drive systems and give a short description of each
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
Spatter problems and poor weld appearance
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires

7. What 2 controls are found on a GMAW set- up?
3
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

8. What is the maximum distance that hard wire can be successfully pushed?
Pressure vessels and the piping industry
V groove or U groove
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas

9. Why must CO2 cylinders be used in the vertical position?
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate

10. 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)
Guns
Constant current (CC)
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11. What effect does increasing and decreasing the inductance have on the weld?
The negative side of a welding unit
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Insufficient current to melt the wire off cleanly
20 to 200 times per second

12. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
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Gas metal arc welding

13. What output on the welding machine is used to rate the duty cycle?
To limit the short circuiting current so that spatter is reduced
Minutes of elapsed time continually run (out of 10 minutes)
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW

14. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
By there current carrying capacity
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

15. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
...
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

16. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow
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
Penetration and burn - off rate of the electrode

17. Why is globular transfer generally avoided with GMAW?
Pressure vessels and the piping industry
Guns
Spatter problems and poor weld appearance
Constant current (CC)

18. List several industries that would use GMAW
If you dont know this check your phone
Guns
The Arc voltage
Pressure vessels and the piping industry

19. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
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
The time rate of response for the current rise and fall
3

20. What does inductance control?
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
To limit the short circuiting current so that spatter is reduced
Dry ice can form within the flow control openings and cause blockage of shielding gas

21. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity
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

22. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Shielding the molten weld metal from atmospheric contamination
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed
...

23. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly
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
12 to 22 arc volts

24. What does the term GMAW identify?
5.8 to 12.5 L/min
Gas metal arc welding
Duty cycle
Reducing the gas source pressure to a constant working pressure

25. What is the preferred drive roll design for solid wires?
The Arc voltage
The negative side of a welding unit
Cause flaking - which can clog the liner and contact tube
V groove or U groove

26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
These terms are quite restrictive and often technically incorrect
Duty cycle
Welding process that joins metals by heating them with an electric arc
85%

27. List the three methods of metal transfer with GMAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Shielding the molten weld metal from atmospheric contamination

28. 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
12 to 22 arc volts
Flux cored wires
Constant current (CC)

29. How are GMAW guns rated?
By there current carrying capacity
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall
...

30. What is an advantage of pulsed arc transfer with GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant current (CC)

31. What is the purpose of the shielding gas used in GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode

32. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Welding process that joins metals by heating them with an electric arc
Constant current (CC)
Flux cored wires

33. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
5.8 to 12.5 L/min
Aluminum wire
12 to 22 arc volts

34. List the basic equipment requirements for the GMAW process
The negative side of a welding unit
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Generally not as accurate

35. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed - Voltage control

36. What is the purpose of a regulator and what does it indicate on its gauges?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
Reducing the gas source pressure to a constant working pressure
15 feet (4.5 meters)

37. What does the abbreviation NEMA stand for?
Cause flaking - which can clog the liner and contact tube
SMAW - GTAW
National Electrical Manufactures Association
Higher 26 to 35 arc volts

38. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced
Dry ice can form within the flow control openings and cause blockage of shielding gas

39. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Constant current (CC)
Gives arc voltage values to the control system of the feeder
Wire feed speed
Welding process that joins metals by heating them with an electric arc

40. Give a brief description of the GMAW process
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
Welding process that joins metals by heating them with an electric arc

41. What does a flowmeter do and what does it measure?
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire

42. What 2 organizations designate specifications for GMAW wires?
5.8 to 12.5 L/min
AWS and CSA
Pressure vessels and the piping industry
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

43. What wire are knurled drive rolls most commonly used on?
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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

44. Give a description of 'pinch effect'
Controls the rate of flow of a shielding gas to the gun nozzle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
...
Flux cored wires

45. Draw a typical volt amp curve for a machine that is designed for GMAW
20 to 200 times per second
If you dont know this check your phone
Wire feed speed
...

46. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Generally not as accurate

47. What are the 2 types of wire feeders available?
If you dont know this check your phone
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
3

48. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

49. What happens when the electrode extension is increased?
If you dont know this check your phone
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat

50. 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
The Arc voltage
Flux cored wires
3