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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 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)
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input

2. How are GMAW guns rated?
Constant- speed wire feeders and Voltage- sennsing wire feeders
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)
By there current carrying capacity

3. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
To limit the short circuiting current so that spatter is reduced
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

4. List the basic equipment requirements for the GMAW process
12 to 22 arc volts
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding process that joins metals by heating them with an electric arc

5. What is the key advantage of short circuiting transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
Puddle fluidity

6. What does a flowmeter do and what does it measure?
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control

7. How many times per second does short circuiting take place?
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
If you dont know this check your phone
National Electrical Manufactures Association

8. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure - The rate of flow of a shielding gas
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

9. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder

10. 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
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
12 to 22 arc volts

11. When is the metal transferred with short circuit transfer?
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
When the filler wire is in direct contract with the base metal

12. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant current (CC)
Pressure vessels and the piping industry
V groove or U groove
If you dont know this check your phone

13. Why is the term GMAW preferred over MIG or MAG?
Constant voltage (CV)
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

14. What is an advantage of pulsed arc transfer with GMAW?
15 feet (4.5 meters)
5.8 to 12.5 L/min
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second

15. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
The resistace to electrical current flow increases with it. Causing the electrode to heat

16. What does the wire feeder control?
Insufficient current to melt the wire off cleanly
Pressure vessels and the piping industry
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed

17. What 2 organizations designate specifications for GMAW wires?
Constant voltage (CV)
Aluminum wire
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

18. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

19. What controls the wire speed on a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Aluminum wire
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow

20. What happens when the electrode extension is increased?
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat

21. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Spatter problems and poor weld appearance
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs

22. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Pressure vessels and the piping industry
3
...
Shielding the molten weld metal from atmospheric contamination

23. What does inductance control?
Generally not as accurate
Constant current (CC)
Reducing the gas source pressure to a constant working pressure
The time rate of response for the current rise and fall

24. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...

25. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube

26. Why is a fiber washer required and what cylinder gas requires it?
5.8 to 12.5 L/min
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity

27. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Wire feed speed - Voltage control
SMAW - GTAW
If you dont know this check your phone
3

28. Why is a line heater required when using GMAW?
Gas metal arc welding
Constant current (CC)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure vessels and the piping industry

29. What current and polarity is generally used with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

30. What 2 controls are found on a GMAW set- up?
If you dont know this check your phone
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3

31. What is the maximum distance that hard wire can be successfully pushed?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)
National Electrical Manufactures Association

32. What is the preferred drive roll design for solid wires?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Gas metal arc welding
Constant voltage (CV)
V groove or U groove

33. In the GMAW process what does voltage control?
Flux cored wires
Puddle fluidity
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) Reverse Polarity

34. Give a brief description of the GMAW process
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc

35. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)

36. Give a description of 'pinch effect'
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
...
Pressure vessels and the piping industry

37. What is the main purpose of 'slope'?
Generally not as accurate
To limit the short circuiting current so that spatter is reduced
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed - Voltage control

38. What type of power source is used with a constant speed wire feeder?
Constant current (CC)
12 to 22 arc volts
Wire feed speed
Constant voltage (CV)

39. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Flux cored wires
Minimum distortion due to low heat input

40. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

41. What is the effect of too much slope?
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
Dry ice can form within the flow control openings and cause blockage of shielding gas

42. What controls amperage when using 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
Wire feed speed
DCEP (Direct Current Electrode Positive) Reverse Polarity
Cause flaking - which can clog the liner and contact tube

43. What is the purpose of a regulator and what does it indicate on its gauges?
Aluminum wire
Guns
Reducing the gas source pressure to a constant working pressure
Higher 26 to 35 arc volts

44. What does the term GMAW identify?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gas metal arc welding

45. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Flux cored wires
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow

46. What is another term for electrode holders for GMAW?
V groove or U groove
These terms are quite restrictive and often technically incorrect
Guns
5.8 to 12.5 L/min

47. List several industries that would use GMAW
Gas metal arc welding
Duty cycle
Pressure vessels and the piping industry
Speed of the feed motor and - starting / stopping electrode feed

48. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect
Higher 26 to 35 arc volts

49. What are the 2 types of wire feeders available?
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow
Constant- speed wire feeders and Voltage- sennsing wire feeders

50. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate