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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 does inductance control?
The time rate of response for the current rise and fall
The Arc voltage
SMAW - GTAW
These terms are quite restrictive and often technically incorrect

2. What output on the welding machine is used to rate the duty cycle?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone

3. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)
20 to 200 times per second

4. In the GMAW process what does voltage control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity
Aluminum wire
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

5. Why is a line heater required when using GMAW?
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas

6. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Flux cored wires
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry

7. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

8. Give a brief description of the GMAW process
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination

9. When is the metal transferred with short circuit transfer?
AWS and CSA
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder
The resistace to electrical current flow increases with it. Causing the electrode to heat

10. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle
85%
15 feet (4.5 meters)

11. List the factors that determine the mode of metal transfer
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

12. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
If you dont know this check your phone
Constant current (CC)

13. What is the recommended electrode stick- out for .035 solid wire?
Wire feed speed
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder
Aluminum wire

14. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly
Aluminum wire

15. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
...
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance

16. What is the required arc voltage used for short circuit transfer?
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
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer

17. Draw a typical volt amp curve for a machine that is designed for GMAW
V groove or U groove
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant voltage (CV)
If you dont know this check your phone

18. What does the term GMAW identify?
Guns
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding

19. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

20. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Higher 26 to 35 arc volts
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity

21. Why must CO2 cylinders be used in the vertical position?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity
DCEP (Direct Current Electrode Positive) Reverse Polarity

22. What controls the wire speed on a voltage sensing wire feeder?
3
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
The Arc voltage

23. What are the 2 types of wire feeders available?
SMAW - GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts

24. 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)
DCEP (Direct Current Electrode Positive) Reverse Polarity
...

25. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch
...
Gas metal arc welding

26. What does the wire feeder control?
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch

27. 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
To prevent leakage - Carbon Dioxide (CO2)
85%

28. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
20 to 200 times per second
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity

29. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Wire feed speed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle

30. Regulators control_____________ flowmeters SHOW____________.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure - The rate of flow of a shielding gas

31. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs

32. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
Flux cored wires
Wire feed speed

33. What effect does increasing and decreasing the inductance have on the weld?
By there current carrying capacity
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 or Reverse polarity

34. What happens when the electrode extension is increased?
Duty cycle
When the filler wire is in direct contract with the base metal
The resistace to electrical current flow increases with it. Causing the electrode to heat
5.8 to 12.5 L/min

35. What is a typical flow rate of CO2 for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect

36. What is the maximum distance that hard wire can be successfully pushed?
Minimum distortion due to low heat input
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
15 feet (4.5 meters)
12 to 22 arc volts

37. List 3 forms compressed gases may be supplied for welding
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure vessels and the piping industry

38. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode
Pressure vessels and the piping industry

39. 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
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders

40. In the GMAW process what does amperage control?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Penetration and burn - off rate of the electrode

41. What type of power source is used with a constant speed wire feeder?
Gives arc voltage values to the control system of the feeder
20 to 200 times per second
Constant voltage (CV)
...

42. List 3 wire drive systems and give a short description of each
Minimum distortion due to low heat input
Guns
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
To limit the short circuiting current so that spatter is reduced

43. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
12 to 22 arc volts
85%

44. What power sources are used with the GMAW Process?
...
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Motor driven generators - Transformer rectifiers - and Inverter designs
These terms are quite restrictive and often technically incorrect

45. Why is globular transfer generally avoided with GMAW?
Reducing the gas source pressure to a constant working pressure
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Spatter problems and poor weld appearance

46. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder

47. What wire are knurled drive rolls most commonly used on?
Flux cored wires
3
V groove or U groove
Guns

48. What is another term for electrode holders for GMAW?
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
Guns
Wire feed speed - Voltage control

49. 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)
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity

50. What is the preferred drive roll design for solid wires?
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
By there current carrying capacity
Aluminum wire