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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 is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Pressure - The rate of flow of a shielding gas
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%

2. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
National Electrical Manufactures Association
Duty cycle
12 to 22 arc volts

3. What type of power source is used with a constant speed wire feeder?
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant voltage (CV)

4. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Shielding the molten weld metal from atmospheric contamination
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity

5. What is a typical flow rate of CO2 for short circuit transfer?
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
...
3

6. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity
...

7. Why is a fiber washer required and what cylinder gas requires it?
85%
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent leakage - Carbon Dioxide (CO2)
(DCEP) Direct Current Electrode Positive or Reverse polarity

8. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate
To prevent leakage - Carbon Dioxide (CO2)

9. What would be an indication that the drive roll pressure is adjusted correctly?
5.8 to 12.5 L/min
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)

10. What is a solenoid valve and what actuates it?
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate

11. List 3 forms compressed gases may be supplied for welding
Voltage is the force that overcomes resistance to allow amperage flow
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

12. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Gas metal arc welding
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

13. What controls amperage when using GMAW?
Gas metal arc welding
V groove or U groove
Wire feed speed
By there current carrying capacity

14. What is the purpose of the shielding gas used in GMAW?
Constant voltage (CV)
Shielding the molten weld metal from atmospheric contamination
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

15. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
To limit the short circuiting current so that spatter is reduced
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
Cause flaking - which can clog the liner and contact tube

16. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Cause flaking - which can clog the liner and contact tube
3
SMAW - GTAW
If you dont know this check your phone

17. What controls the wire speed on a voltage sensing wire feeder?
3
When the filler wire is in direct contract with the base metal
The Arc voltage
20 to 200 times per second

18. What does the term GMAW identify?
15 feet (4.5 meters)
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
The Arc voltage

19. Give a description of 'pinch effect'
Reducing the gas source pressure to a constant working pressure
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure - The rate of flow of a shielding gas

20. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination

21. What type of power source is commonly used with a voltage sensing wire feeder?
If you dont know this check your phone
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
Constant current (CC)

22. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Higher 26 to 35 arc volts
Duty cycle
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect

23. In the GMAW process what does amperage control?
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode
Short- circuiting transfer - Globular transfer - Spray 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

24. What are the 2 types of wire feeders available?
Wire feed speed - Voltage control
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
15 feet (4.5 meters)

25. Give a brief description of the GMAW process
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc
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

26. 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
15 feet (4.5 meters)
V groove or U groove

27. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder
Spatter problems and poor weld appearance

28. List several industries that would use GMAW
Pressure vessels and the piping industry
1/4 inch to 1/2 inch
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts

29. Draw a typical volt amp curve for a machine that is designed for GMAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone

30. How are GMAW guns rated?
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
By there current carrying capacity
Controls the rate of flow of a shielding gas to the gun nozzle

31. What wire are knurled drive rolls most commonly used on?
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer

32. What is an advantage of pulsed arc transfer with GMAW?
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feed speed
By there current carrying capacity

33. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer

34. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Puddle fluidity
Flux cored wires
Minimum distortion due to low heat input
Higher 26 to 35 arc volts

35. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. What is the preferred drive roll design for solid wires?
Duty cycle
V groove or U groove
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage

37. List the three methods of metal transfer with GMAW
Cause flaking - which can clog the liner and contact tube
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
National Electrical Manufactures Association

38. What effect does increasing and decreasing the inductance have on the weld?
Puddle fluidity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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

39. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
Guns

40. What does inductance control?
Constant current (CC)
The time rate of response for the current rise and fall
Wire feed speed - Voltage control
By there current carrying capacity

41. List the factors that determine the mode of metal transfer
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
These terms are quite restrictive and often technically incorrect
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

42. What is another term for electrode holders for GMAW?
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Guns
85%

43. What does the wire feeder control?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage

44. What does voltage do in an electrical circuit?
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow
Aluminum wire
20 to 200 times per second

45. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts

46. What is the disadvantage of the gauge preset type of regulator/flowmeter?
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
Generally not as accurate
Dry ice can form within the flow control openings and cause blockage of shielding gas
To prevent leakage - Carbon Dioxide (CO2)

47. What is the required arc voltage used for short circuit transfer?
Constant current (CC)
12 to 22 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns

48. How many times per second does short circuiting take place?
V groove or U groove
Duty cycle
The time rate of response for the current rise and fall
20 to 200 times per second

49. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc

50. What processes are constant current (CC) power sources designed to be used with?
Minutes of elapsed time continually run (out of 10 minutes)
Welding process that joins metals by heating them with an electric arc
SMAW - GTAW
1/4 inch to 1/2 inch