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Test your basic knowledge |

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. How are GMAW guns rated?
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V groove or U groove
Generally not as accurate
By there current carrying capacity

2. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
The time rate of response for the current rise and fall

3. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Generally not as accurate
Short- circuiting transfer - Globular transfer - Spray transfer
3

4. What is another term for electrode holders for GMAW?
Guns
These terms are quite restrictive and often technically incorrect
Pressure vessels and the piping industry
SMAW - GTAW

5. What does inductance control?
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
The time rate of response for the current rise and fall
If you dont know this check your phone

6. What power sources are used with the GMAW Process?
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
...
Constant- speed wire feeders and Voltage- sennsing wire feeders

8. What processes are constant current (CC) power sources designed to be used with?
Shielding the molten weld metal from atmospheric contamination
Wire feed speed
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure

9. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Puddle fluidity
Short- circuiting transfer - Globular transfer - Spray transfer
Generally not as accurate

10. Why is globular transfer generally avoided with GMAW?
Cause flaking - which can clog the liner and contact tube
Short- circuiting transfer - Globular transfer - Spray transfer
Spatter problems and poor weld appearance
Gas metal arc welding

11. In the GMAW process what does amperage control?
12 to 22 arc volts
When the filler wire is in direct contract with the base metal
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Penetration and burn - off rate of the electrode

12. Give a description of 'pinch effect'
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
By there current carrying capacity

13. In the GMAW process what does voltage control?
Guns
Insufficient current to melt the wire off cleanly
Puddle fluidity
DCEP (Direct Current Electrode Positive) Reverse Polarity

14. What type of power source is commonly used with a voltage sensing wire feeder?
3
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle

15. A pull type drive system is usually used on what type of material?
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
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder
Aluminum wire

16. What is the purpose of the shielding gas used in GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Generally not as accurate

17. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Pressure vessels and the piping industry
Gives arc voltage values to the control system of the feeder
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle

18. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

19. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
Generally not as accurate

20. List the basic equipment requirements for the GMAW process
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
20 to 200 times per second

21. What is a typical flow rate of CO2 for short circuit transfer?
...
5.8 to 12.5 L/min
Wire feed speed
Spatter problems and poor weld appearance

22. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Duty cycle
Constant voltage (CV)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
(DCEP) Direct Current Electrode Positive or Reverse polarity

23. What output on the welding machine is used to rate the duty cycle?
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)

24. List 3 forms compressed gases may be supplied for welding
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

25. What would be an indication that the drive roll pressure is adjusted correctly?
5.8 to 12.5 L/min
Guns
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding process that joins metals by heating them with an electric arc

26. How many times per second does short circuiting take place?
Higher 26 to 35 arc volts
20 to 200 times per second
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube

27. What 2 organizations designate specifications for GMAW wires?
National Electrical Manufactures Association
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
Reducing the gas source pressure to a constant working pressure

28. What 2 controls are found on a GMAW set- up?
When the filler wire is in direct contract with the base metal
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control

29. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
85%
The time rate of response for the current rise and fall
The resistace to electrical current flow increases with it. Causing the electrode to heat
Higher 26 to 35 arc volts

30. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly

31. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
Reducing the gas source pressure to a constant working pressure
Cause flaking - which can clog the liner and contact tube

32. 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
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
By there current carrying capacity

33. What are the 2 types of wire feeders available?
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
Flux cored wires
Constant- speed wire feeders and Voltage- sennsing wire feeders

34. What current and polarity is generally used with GMAW?
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity

35. What is an advantage of pulsed arc transfer with GMAW?
Aluminum wire
Wire feed speed - Voltage control
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

36. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
Aluminum wire
Gas metal arc welding

37. What effect does increasing and decreasing the inductance have on the weld?
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

38. What controls amperage when using GMAW?
Wire feed speed
Insufficient current to melt the wire off cleanly
Spatter problems and poor weld appearance
Short- circuiting transfer - Globular transfer - Spray transfer

39. Give a brief description of the GMAW process
Wire feed speed
Generally not as accurate
Welding process that joins metals by heating them with an electric arc
Wire feeds smoothly (yet will slip should a problem occur in the gun)

40. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
...
Puddle fluidity
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. List the three methods of metal transfer with GMAW
Guns
Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)
When the filler wire is in direct contract with the base metal

42. List the factors that determine the mode of metal transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone

43. What does the term GMAW identify?
Puddle fluidity
Gas metal arc welding
Guns
If you dont know this check your phone

44. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
Motor driven generators - Transformer rectifiers - and Inverter designs
20 to 200 times per second

45. What is the effect of too much slope?
20 to 200 times per second
Insufficient current to melt the wire off cleanly
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

46. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

47. Why must CO2 cylinders be used in the vertical position?
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min

48. What does the wire feeder control?
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed
Guns

49. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Insufficient current to melt the wire off cleanly

50. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Constant current (CC)
3
Voltage is the force that overcomes resistance to allow amperage flow