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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 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
(DCEP) Direct Current Electrode Positive or Reverse polarity
...
Pressure - The rate of flow of a shielding gas

2. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Gives arc voltage values to the control system of the feeder
Cause flaking - which can clog the liner and contact tube
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination

3. How many times per second does short circuiting take place?
Motor driven generators - Transformer rectifiers - and Inverter designs
20 to 200 times per second
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity

4. Why is the term GMAW preferred over MIG or MAG?
3
Flux cored wires
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

5. What power sources are used with the GMAW Process?
Speed of the feed motor and - starting / stopping electrode feed
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min
Shielding the molten weld metal from atmospheric contamination

6. List the three methods of metal transfer with GMAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

7. List several industries that would use GMAW
Higher 26 to 35 arc volts
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry

8. What output on the welding machine is used to rate the duty cycle?
The time rate of response for the current rise and fall
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode

9. A pull type drive system is usually used on what type of material?
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced

10. How are GMAW guns rated?
Constant voltage (CV)
20 to 200 times per second
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)

11. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

12. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Guns
5.8 to 12.5 L/min
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Shielding the molten weld metal from atmospheric contamination
Higher 26 to 35 arc volts
Wire feed speed - Voltage control

14. In the GMAW process what does voltage control?
National Electrical Manufactures Association
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
These terms are quite restrictive and often technically incorrect

15. 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)
Generally not as accurate
Puddle fluidity
Constant voltage (CV)

16. What does the abbreviation NEMA stand for?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Short- circuiting transfer - Globular transfer - Spray transfer
When the filler wire is in direct contract with the base metal
National Electrical Manufactures Association

17. What is the required arc voltage used for short circuit transfer?
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min
Shielding the molten weld metal from atmospheric contamination
12 to 22 arc volts

18. What is another term for electrode holders for GMAW?
Pressure vessels and the piping industry
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns

19. What type of power source is commonly used with a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
Constant current (CC)

20. What does the term GMAW identify?
If you dont know this check your phone
If you dont know this check your phone
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity

21. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Gas metal arc welding
Wire feed speed
3
...

22. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube

23. What is the main purpose of 'slope'?
Constant current (CC)
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
Generally not as accurate

24. In the GMAW process what does amperage 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
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)
Constant voltage (CV)

25. Give a brief description of the GMAW process
When the filler wire is in direct contract with the base metal
Wire feed speed
Welding process that joins metals by heating them with an electric arc
Puddle fluidity

26. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Penetration and burn - off rate of the electrode

27. List 3 forms compressed gases may be supplied for welding
Gives arc voltage values to the control system of the feeder
Constant current (CC)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

28. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
By there current carrying capacity

29. List the factors that determine the mode of metal transfer
Voltage is the force that overcomes resistance to allow amperage flow
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
1/4 inch to 1/2 inch

30. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder

31. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit

32. Why must CO2 cylinders be used in the vertical position?
To prevent leakage - Carbon Dioxide (CO2)
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)

33. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
3
Generally not as accurate

34. What is the key advantage of short circuiting transfer?
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Higher 26 to 35 arc volts
Minimum distortion due to low heat input

35. What is the effect of too much slope?
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly
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

36. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The time rate of response for the current rise and fall
15 feet (4.5 meters)
...

37. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced

38. What does inductance control?
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The time rate of response for the current rise and fall

39. What type of power source is used with a constant speed wire feeder?
15 feet (4.5 meters)
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
By there current carrying capacity

40. What is the maximum distance that hard wire can be successfully pushed?
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
Constant current (CC)
If you dont know this check your phone

41. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
20 to 200 times per second
Constant voltage (CV)
85%
V groove or U groove

42. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Guns
Generally not as accurate
National Electrical Manufactures Association

43. What current and polarity is generally used with GMAW?
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Reducing the gas source pressure to a constant working pressure
DCEP (Direct Current Electrode Positive) Reverse Polarity

44. What does a flowmeter do and what does it measure?
The resistace to electrical current flow increases with it. Causing the electrode to heat
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
Minimum distortion due to low heat input

45. Regulators control_____________ flowmeters SHOW____________.
If you dont know this check your phone
85%
1/4 inch to 1/2 inch
Pressure - The rate of flow of a shielding gas

46. What 2 organizations designate specifications for GMAW wires?
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
12 to 22 arc volts
Guns

47. Why is a line heater required when using GMAW?
The Arc voltage
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate

48. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone

49. What is the purpose of the shielding gas used in GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
SMAW - GTAW

50. What is the purpose of a regulator and what does it indicate on its gauges?
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed
Reducing the gas source pressure to a constant working pressure
Aluminum wire