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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. How are GMAW guns rated?
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
Wire feed speed
Constant voltage (CV)

2. Draw a typical volt amp curve for a machine that is designed for GMAW
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Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

3. Why must CO2 cylinders be used in the vertical position?
Duty cycle
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance

4. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
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3
Reducing the gas source pressure to a constant working pressure
Pressure vessels and the piping industry

5. With straight polarity where is 2/3 of the arc energy?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
The negative side of a welding unit
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6. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed
Shielding the molten weld metal from atmospheric contamination

7. What is the purpose of the shielding gas used in GMAW?
Reducing the gas source pressure to a constant working pressure
The Arc voltage
AWS and CSA
Shielding the molten weld metal from atmospheric contamination

8. List the basic equipment requirements for the GMAW process
When the filler wire is in direct contract with the base metal
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

9. What 2 organizations designate specifications for GMAW wires?
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect
AWS and CSA

10. List the factors that determine the mode of metal transfer
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit

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

12. What is another term for electrode holders for GMAW?
Duty cycle
Higher 26 to 35 arc volts
Guns
12 to 22 arc volts

13. What is the required arc voltage used for short circuit transfer?
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Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
12 to 22 arc volts

14. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
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
12 to 22 arc volts
When the filler wire is in direct contract with the base metal

15. What is the purpose of a regulator and what does it indicate on its gauges?
Spatter problems and poor weld appearance
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
Reducing the gas source pressure to a constant working pressure

16. In the GMAW process what does voltage control?
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
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Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

17. What processes are constant current (CC) power sources designed to be used with?
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry
...
SMAW - GTAW

18. What output on the welding machine is used to rate the duty cycle?
85%
Wire feed speed - Voltage control
Gas metal arc welding
Minutes of elapsed time continually run (out of 10 minutes)

19. When is the metal transferred with short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
When the filler wire is in direct contract with the base metal
By there current carrying capacity
Pressure - The rate of flow of a shielding gas

20. List the three methods of metal transfer with GMAW
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer

21. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)

22. What does inductance control?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall
Gives arc voltage values to the control system of the feeder
Generally not as accurate

23. A 10 minute cycle of welding time vs cooling time a given machine can handle.
15 feet (4.5 meters)
Duty cycle
The negative side of a welding unit
Gas metal arc welding

24. What is a solenoid valve and what actuates it?
Gas metal arc welding
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts
The negative side of a welding unit

25. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
12 to 22 arc volts
...
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure vessels and the piping industry

26. What type of power source is used with a constant speed wire feeder?
Guns
Constant voltage (CV)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Speed of the feed motor and - starting / stopping electrode feed

27. What type of power source is commonly used with a voltage sensing wire feeder?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant current (CC)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW

28. What is the preferred drive roll design for solid wires?
When the filler wire is in direct contract with the base metal
V groove or U groove
To limit the short circuiting current so that spatter is reduced
Guns

29. 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
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

30. List 3 wire drive systems and give a short description of each
Motor driven generators - Transformer rectifiers - and Inverter designs
Insufficient current to melt the wire off cleanly
...
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

31. In the GMAW process what does amperage control?
Speed of the feed motor and - starting / stopping electrode feed
AWS and CSA
Penetration and burn - off rate of the electrode
Generally not as accurate

32. What is the effect of too much slope?
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly
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SMAW - GTAW

33. What would be an indication that the drive roll pressure is adjusted correctly?
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Minutes of elapsed time continually run (out of 10 minutes)

34. What are the 2 types of wire feeders available?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders

35. What effect does increasing and decreasing the inductance have on the weld?
The Arc voltage
Constant voltage (CV)
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

36. A pull type drive system is usually used on what type of material?
Aluminum wire
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc

37. What is the maximum distance that hard wire can be successfully pushed?
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding
15 feet (4.5 meters)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

38. List several industries that would use GMAW
Cause flaking - which can clog the liner and contact tube
Gives arc voltage values to the control system of the feeder
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure vessels and the piping industry

39. What current and polarity is generally used with GMAW?
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity
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

40. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
When the filler wire is in direct contract with the base metal
Cause flaking - which can clog the liner and contact tube
Wire feed speed
National Electrical Manufactures Association

41. Why is a line heater required when using GMAW?
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
The negative side of a welding unit
Constant voltage (CV)

42. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
5.8 to 12.5 L/min
Insufficient current to melt the wire off cleanly
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Generally not as accurate

43. What does the abbreviation NEMA stand for?
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity
National Electrical Manufactures Association
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

44. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Cause flaking - which can clog the liner and contact tube
85%
To limit the short circuiting current so that spatter is reduced
(DCEP) Direct Current Electrode Positive or Reverse polarity

45. What does the term GMAW identify?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer

46. What happens when the electrode extension is increased?
Pressure - The rate of flow of a shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
...

47. What is the main purpose of 'slope'?
Gas metal arc welding
Constant current (CC)
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity

48. Give a brief description of the GMAW process
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc

49. What does voltage do in an electrical circuit?
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow
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
When the filler wire is in direct contract with the base metal

50. What wire are knurled drive rolls most commonly used on?
Wire feed speed - Voltage control
Flux cored wires
Gas metal arc welding
Guns