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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.
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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 effect of too much slope?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

2. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Cause flaking - which can clog the liner and contact tube
To prevent drawing of liquid CO2 (Carbon Dioxide)

3. What are the 2 types of wire feeders available?
Gas metal arc welding
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts

4. What is the main purpose of 'slope'?
AWS and CSA
Constant voltage (CV)
To limit the short circuiting current so that spatter is reduced
These terms are quite restrictive and often technically incorrect

5. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
To limit the short circuiting current so that spatter is reduced
Generally not as accurate
Constant current (CC)

6. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Constant current (CC)

7. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall
Generally not as accurate

8. What is the key advantage of short circuiting transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
By there current carrying capacity
These terms are quite restrictive and often technically incorrect
Minimum distortion due to low heat input

9. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns
Penetration and burn - off rate of the electrode

10. 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
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)

11. What output on the welding machine is used to rate the duty cycle?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
The resistace to electrical current flow increases with it. Causing the electrode to heat

12. What is the purpose of a regulator and what does it indicate on its gauges?
Cause flaking - which can clog the liner and contact tube
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Reducing the gas source pressure to a constant working pressure

13. What would be an indication that the drive roll pressure is adjusted correctly?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)

14. Regulators control_____________ flowmeters SHOW____________.
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)

15. How are GMAW guns rated?
Constant current (CC)
If you dont know this check your phone
By there current carrying capacity
Wire feed speed

16. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity

17. A 10 minute cycle of welding time vs cooling time a given machine can handle.
12 to 22 arc volts
Duty cycle
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity

18. What is the preferred drive roll design for solid wires?
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
5.8 to 12.5 L/min

19. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Puddle fluidity
Reducing the gas source pressure to a constant working pressure

20. What controls amperage when using GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The Arc voltage
Wire feed speed
12 to 22 arc volts

21. In the GMAW process what does voltage control?
These terms are quite restrictive and often technically incorrect
Short- circuiting transfer - Globular transfer - Spray transfer
Puddle fluidity
12 to 22 arc volts

22. What type of power source is commonly used with a voltage sensing wire feeder?
The Arc voltage
Constant current (CC)
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect

23. What wire are knurled drive rolls most commonly used on?
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
Minimum distortion due to low heat input

24. What effect does increasing and decreasing the inductance have on the weld?
Motor driven generators - Transformer rectifiers - and Inverter designs
Puddle fluidity
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

25. Draw a typical volt amp curve for a machine that is designed for GMAW
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
The time rate of response for the current rise and fall
Wire feeds smoothly (yet will slip should a problem occur in the gun)

26. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association
The time rate of response for the current rise and fall

27. In the GMAW process what does amperage control?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode
(DCEP) Direct Current Electrode Positive or Reverse polarity

28. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit

29. What is an advantage of pulsed arc transfer with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow
3
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

30. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal
The Arc voltage
Constant voltage (CV)

31. What is the maximum distance that hard wire can be successfully pushed?
The time rate of response for the current rise and fall
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)
Wire feed speed - Voltage control

32. List the basic equipment requirements for the GMAW process
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
When the filler wire is in direct contract with the base metal

33. What type of power source is used with a constant speed wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
Constant voltage (CV)
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
Puddle fluidity

34. What does the wire feeder control?
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed

35. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Puddle fluidity
Reducing the gas source pressure to a constant working pressure
These terms are quite restrictive and often technically incorrect

36. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
Gas metal arc welding

37. What power sources are used with the GMAW Process?
15 feet (4.5 meters)
5.8 to 12.5 L/min
Motor driven generators - Transformer rectifiers - and Inverter designs
85%

38. List several industries that would use GMAW
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry
Gas metal arc welding

39. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Duty cycle
Cause flaking - which can clog the liner and contact tube
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

40. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
Puddle fluidity
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

41. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
Aluminum wire
3

42. What is the required arc voltage used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
12 to 22 arc volts
If you dont know this check your phone

43. How many times per second does short circuiting take place?
Guns
Duty cycle
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)

44. Give a description of 'pinch effect'
Wire feed speed
15 feet (4.5 meters)
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

45. What is another term for electrode holders for GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Cause flaking - which can clog the liner and contact tube
Controls the rate of flow of a shielding gas to the gun nozzle
Guns

46. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent leakage - Carbon Dioxide (CO2)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Dry ice can form within the flow control openings and cause blockage of shielding gas

47. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity

48. A pull type drive system is usually used on what type of material?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc

49. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

50. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
...
When the filler wire is in direct contract with the base metal