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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 recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
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Penetration and burn - off rate of the electrode
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. Why must CO2 cylinders be used in the vertical position?
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
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3. What effect does increasing and decreasing the inductance have on the weld?
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced
1/4 inch to 1/2 inch
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

4. What is the effect of too much slope?
5.8 to 12.5 L/min
Aluminum wire
Gas metal arc welding
Insufficient current to melt the wire off cleanly

5. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
SMAW - GTAW
Flux cored wires
To limit the short circuiting current so that spatter is reduced

6. In the GMAW process what does amperage control?
Speed of the feed motor and - starting / stopping electrode feed
Penetration and burn - off rate of the electrode
Pressure vessels and the piping industry
The time rate of response for the current rise and fall

7. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Reducing the gas source pressure to a constant working pressure
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder

8. A 10 minute cycle of welding time vs cooling time a given machine can handle.
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
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc

9. What does the abbreviation NEMA stand for?
To prevent drawing of liquid CO2 (Carbon Dioxide)
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V groove or U groove
National Electrical Manufactures Association

10. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Minutes of elapsed time continually run (out of 10 minutes)
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Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Aluminum wire

11. What does voltage do in an electrical circuit?
These terms are quite restrictive and often technically incorrect
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

12. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
Wire feed speed - Voltage control

13. Regulators control_____________ flowmeters SHOW____________.
Welding process that joins metals by heating them with an electric arc
The Arc voltage
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
Pressure - The rate of flow of a shielding gas

14. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Gas metal arc welding
3
Guns

15. What power sources are used with the GMAW Process?
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs

16. A pull type drive system is usually used on what type of material?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Aluminum wire
When the filler wire is in direct contract with the base metal

17. Why is a fiber washer required and what cylinder gas requires it?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Penetration and burn - off rate of the electrode
To prevent leakage - Carbon Dioxide (CO2)

18. What current and polarity is generally used with GMAW?
3
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA

19. Draw a typical volt amp curve for a machine that is designed for GMAW
Reducing the gas source pressure to a constant working pressure
...
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

20. What 2 organizations designate specifications for GMAW wires?
Gas metal arc welding
...
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
AWS and CSA

21. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
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
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow

22. What type of power source is used with a constant speed wire feeder?
Insufficient current to melt the wire off cleanly
The negative side of a welding unit
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder

23. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity
20 to 200 times per second

24. What controls amperage when using GMAW?
Higher 26 to 35 arc volts
The negative side of a welding unit
Wire feed speed
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25. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
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
Duty cycle

26. What does the term GMAW identify?
Gas metal arc welding
The Arc voltage
Duty cycle
3

27. What does inductance control?
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
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

28. How are GMAW guns rated?
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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

29. What is the key advantage of short circuiting transfer?
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
Penetration and burn - off rate of the electrode

30. Why is globular transfer generally avoided with GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
20 to 200 times per second
Guns
Spatter problems and poor weld appearance

31. List 3 forms compressed gases may be supplied for welding
85%
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3

32. List several industries that would use GMAW
To limit the short circuiting current so that spatter is reduced
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
Pressure vessels and the piping industry

33. List the factors that determine the mode of metal transfer
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Guns
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

34. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance
3

35. 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
Motor driven generators - Transformer rectifiers - and Inverter designs
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. What controls the wire speed on a voltage sensing wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
Duty cycle

37. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
AWS and CSA
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed
(DCEP) Direct Current Electrode Positive or Reverse polarity

38. Why is the term GMAW preferred over MIG or MAG?
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas

39. List the three methods of metal transfer with GMAW
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer
5.8 to 12.5 L/min
12 to 22 arc volts

40. What is the main purpose of 'slope'?
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

41. What is the maximum distance that hard wire can be successfully pushed?
Guns
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
15 feet (4.5 meters)

42. What is the disadvantage of the gauge preset type of regulator/flowmeter?
The time rate of response for the current rise and fall
To limit the short circuiting current so that spatter is reduced
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
Generally not as accurate

43. What is the preferred drive roll design for solid wires?
The resistace to electrical current flow increases with it. Causing the electrode to heat
V groove or U groove
Generally not as accurate
The negative side of a welding unit

44. What is the purpose of the shielding gas used in GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)

45. What is another term for electrode holders for GMAW?
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
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect

46. What output on the welding machine is used to rate the duty cycle?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed
3

47. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
...
Duty cycle

48. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity

49. Give a description of 'pinch effect'
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
1/4 inch to 1/2 inch

50. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feed speed - Voltage control