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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. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Controls the rate of flow of a shielding gas to the gun nozzle
Generally not as accurate
Cause flaking - which can clog the liner and contact tube

2. What effect does increasing and decreasing the inductance have on the weld?
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
...
Wire feed speed

3. What is another term for electrode holders for GMAW?
Minimum distortion due to low heat input
Guns
Duty cycle
DCEP (Direct Current Electrode Positive) Reverse Polarity

4. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
These terms are quite restrictive and often technically incorrect

5. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
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)

6. What current and polarity is generally used with GMAW?
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

7. What is the main purpose of 'slope'?
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced

8. What 2 controls are found on a GMAW set- up?
To limit the short circuiting current so that spatter is reduced
Duty cycle
Wire feed speed - Voltage control
3

9. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry

10. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)
Short- circuiting transfer - Globular transfer - Spray transfer

11. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
Duty cycle

12. Why is a line heater required when using GMAW?
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas

13. List the basic equipment requirements for the GMAW process
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance

14. What is an advantage of pulsed arc transfer with GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
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
To prevent leakage - Carbon Dioxide (CO2)

15. What is the key advantage of short circuiting transfer?
These terms are quite restrictive and often technically incorrect
V groove or U groove
...
Minimum distortion due to low heat input

16. Why must CO2 cylinders be used in the vertical position?
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)

17. What controls amperage when using GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

18. Give a brief description of the GMAW process
Short- circuiting transfer - Globular transfer - Spray transfer
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
Welding process that joins metals by heating them with an electric arc

19. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The negative side of a welding unit
3
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove

20. Give a description of 'pinch effect'
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feeds smoothly (yet will slip should a problem occur in the gun)

21. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Insufficient current to melt the wire off cleanly
85%
Motor driven generators - Transformer rectifiers - and Inverter designs

22. What does a flowmeter do and what does it measure?
Higher 26 to 35 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

23. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
DCEP (Direct Current Electrode Positive) Reverse Polarity
Duty cycle
Shielding the molten weld metal from atmospheric contamination

24. What is a typical flow rate of CO2 for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas

25. In the GMAW process what does amperage control?
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode
V groove or U groove
Dry ice can form within the flow control openings and cause blockage of shielding gas

26. What does voltage do in an electrical circuit?
SMAW - GTAW
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Minimum distortion due to low heat input

27. 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
Gives arc voltage values to the control system of the feeder
The negative side of a welding unit

28. 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
Insufficient current to melt the wire off cleanly
Higher 26 to 35 arc volts
Puddle fluidity

29. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Aluminum wire
If you dont know this check your phone

30. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Guns
Shielding the molten weld metal from atmospheric contamination
Pressure vessels and the piping industry

31. What does inductance control?
AWS and CSA
The time rate of response for the current rise and fall
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch

32. Draw a typical volt amp curve for a machine that is designed for GMAW
Aluminum wire
If you dont know this check your phone
The Arc voltage
Pressure vessels and the piping industry

33. What wire are knurled drive rolls most commonly used on?
1/4 inch to 1/2 inch
To prevent leakage - Carbon Dioxide (CO2)
Flux cored wires
Shielding the molten weld metal from atmospheric contamination

34. How many times per second does short circuiting take place?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
20 to 200 times per second
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

35. In the GMAW process what does voltage control?
3
(DCEP) Direct Current Electrode Positive or Reverse polarity
Puddle fluidity
Spatter problems and poor weld appearance

36. List the three methods of metal transfer with GMAW
Gives arc voltage values to the control system of the feeder
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

37. List the factors that determine the mode of metal transfer
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

38. What does the abbreviation NEMA stand for?
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association
Higher 26 to 35 arc volts
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

39. What type of power source is commonly used with a voltage sensing wire feeder?
Spatter problems and poor weld appearance
Constant current (CC)
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity

40. List 3 forms compressed gases may be supplied for welding
If you dont know this check your phone
The time rate of response for the current rise and fall
If you dont know this check your phone
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

41. What is the purpose of the shielding gas used in GMAW?
Insufficient current to melt the wire off cleanly
Guns
Shielding the molten weld metal from atmospheric contamination
Wire feed speed

42. Why is globular transfer generally avoided with GMAW?
Constant voltage (CV)
Spatter problems and poor weld appearance
Duty cycle
Cause flaking - which can clog the liner and contact tube

43. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination
The time rate of response for the current rise and fall

44. What 2 organizations designate specifications for GMAW wires?
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

45. What is the maximum distance that hard wire can be successfully pushed?
If you dont know this check your phone
Aluminum wire
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

46. What type of power source is used with a constant speed wire feeder?
The Arc voltage
These terms are quite restrictive and often technically incorrect
Constant current (CC)
Constant voltage (CV)

47. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
By there current carrying capacity

48. List several industries that would use GMAW
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure

49. 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
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
Shielding the molten weld metal from atmospheric contamination

50. What is the effect of too much slope?
Duty cycle
3
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)