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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. Why is a fiber washer required and what cylinder gas requires it?
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)
The Arc voltage

2. 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
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder
20 to 200 times per second

3. What is an advantage of pulsed arc transfer with GMAW?
AWS and CSA
Pressure - The rate of flow of a shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Flux cored wires

4. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder

5. What is the required arc voltage used for short circuit transfer?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer
When the filler wire is in direct contract with the base metal
12 to 22 arc volts

6. What is the purpose of a regulator and what does it indicate on its gauges?
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
Reducing the gas source pressure to a constant working pressure
Generally not as accurate
Constant- speed wire feeders and Voltage- sennsing wire feeders

7. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
SMAW - GTAW
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity

8. What happens when the electrode extension is increased?
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant voltage (CV)
20 to 200 times per second

9. What does the wire feeder control?
Pressure vessels and the piping industry
Gas metal arc welding
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed

10. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Flux cored wires
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

11. Give a description of 'pinch effect'
Pressure - The rate of flow of a shielding gas
Higher 26 to 35 arc volts
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

12. In the GMAW process what does voltage control?
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity
15 feet (4.5 meters)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

13. What power sources are used with the GMAW Process?
Gas metal arc welding
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
Motor driven generators - Transformer rectifiers - and Inverter designs

14. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Pressure - The rate of flow of a shielding gas
Guns
Gas metal arc welding
3

15. What is the preferred drive roll design for solid wires?
Flux cored wires
Constant voltage (CV)
20 to 200 times per second
V groove or U groove

16. What does a flowmeter do and what does it measure?
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
Controls the rate of flow of a shielding gas to the gun nozzle
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs

17. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
3
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube

18. Regulators control_____________ flowmeters SHOW____________.
Insufficient current to melt the wire off cleanly
Aluminum wire
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas

19. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Aluminum wire
...
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

20. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc

21. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Motor driven generators - Transformer rectifiers - and Inverter designs

22. Why is a line heater required when using GMAW?
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gives arc voltage values to the control system of the feeder

23. Give a brief description of the GMAW process
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
These terms are quite restrictive and often technically incorrect
3

24. List 3 forms compressed gases may be supplied for welding
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
AWS and CSA
To limit the short circuiting current so that spatter is reduced

25. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
(DCEP) Direct Current Electrode Positive or Reverse polarity

26. What are the 2 types of wire feeders available?
By there current carrying capacity
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders
...

27. What controls amperage when using GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent leakage - Carbon Dioxide (CO2)

28. 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)
V groove or U groove
Puddle fluidity
Gives arc voltage values to the control system of the feeder

29. List the factors that determine the mode of metal transfer
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

30. What is the recommended electrode stick- out for .035 solid wire?
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
V groove or U groove

31. What is another term for electrode holders for GMAW?
Guns
AWS and CSA
Pressure - The rate of flow of a shielding gas
National Electrical Manufactures Association

32. What 2 controls are found on a GMAW set- up?
By there current carrying capacity
85%
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 - Voltage control

33. What effect does increasing and decreasing the inductance have on the weld?
Flux cored wires
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow
Cause flaking - which can clog the liner and contact tube

34. What is a typical flow rate of CO2 for short circuit transfer?
Welding process that joins metals by heating them with an electric arc
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

35. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Wire feed speed - Voltage control
Gives arc voltage values to the control system of the feeder
15 feet (4.5 meters)
1/4 inch to 1/2 inch

36. What 2 organizations designate specifications for GMAW wires?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
V groove or U groove
AWS and CSA

37. What wire are knurled drive rolls most commonly used on?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires

38. What is the main purpose of 'slope'?
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
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire

39. What is the key advantage of short circuiting transfer?
Voltage is the force that overcomes resistance to allow amperage flow
SMAW - GTAW
Higher 26 to 35 arc volts
Minimum distortion due to low heat input

40. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

41. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Pressure - The rate of flow of a shielding gas
Generally not as accurate
20 to 200 times per second
Penetration and burn - off rate of the electrode

42. How are GMAW guns rated?
Constant- speed wire feeders and Voltage- sennsing wire feeders
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal

43. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Dry ice can form within the flow control openings and cause blockage of shielding gas
Duty cycle
Constant current (CC)
Cause flaking - which can clog the liner and contact tube

44. Draw a typical volt amp curve for a machine that is designed for GMAW
Puddle fluidity
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
12 to 22 arc volts

45. List the basic equipment requirements for the GMAW process
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
Pressure vessels and the piping industry
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

46. What does the term GMAW identify?
Reducing the gas source pressure to a constant working pressure
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding
Aluminum wire

47. What type of power source is used with a constant speed wire feeder?
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)

48. Why is the term GMAW preferred over MIG or MAG?
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode

49. List several industries that would use GMAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs

50. List 3 wire drive systems and give a short description of each
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
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)