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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 must CO2 cylinders be used in the vertical position?
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity

2. List the three methods of metal transfer with GMAW
Constant voltage (CV)
Pressure vessels and the piping industry
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs

3. Why is the term GMAW preferred over MIG or MAG?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Controls the rate of flow of a shielding gas to the gun nozzle
V groove or U groove
These terms are quite restrictive and often technically incorrect

4. What controls the wire speed on a voltage sensing wire feeder?
Higher 26 to 35 arc volts
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Voltage is the force that overcomes resistance to allow amperage flow

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding

6. What controls amperage when using GMAW?
Aluminum wire
Gives arc voltage values to the control system of the feeder
Duty cycle
Wire feed speed

7. What is the maximum distance that hard wire can be successfully pushed?
SMAW - GTAW
If you dont know this check your phone
15 feet (4.5 meters)
Dry ice can form within the flow control openings and cause blockage of shielding gas

8. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)
Short- circuiting transfer - Globular transfer - Spray transfer

9. What does a flowmeter do and what does it measure?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle

10. What effect does increasing and decreasing the inductance have on the weld?
Reducing the gas source pressure to a constant working pressure
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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

11. What 2 controls are found on a GMAW set- up?
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed - Voltage control

12. List several industries that would use GMAW
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
SMAW - GTAW
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)

14. What is the required arc voltage used for short circuit transfer?
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
1/4 inch to 1/2 inch
5.8 to 12.5 L/min
12 to 22 arc volts

15. Give a description of 'pinch effect'
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns

16. When is the metal transferred with 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
Spatter problems and poor weld appearance
Short- circuiting transfer - Globular transfer - Spray transfer

17. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

18. Draw a typical volt amp curve for a machine that is designed for GMAW
The Arc voltage
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
Voltage is the force that overcomes resistance to allow amperage flow

19. What is the main purpose of 'slope'?
15 feet (4.5 meters)
Pressure vessels and the piping industry
To limit the short circuiting current so that spatter is reduced
Welding process that joins metals by heating them with an electric arc

20. List 3 wire drive systems and give a short description of each
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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
The time rate of response for the current rise and fall
National Electrical Manufactures Association

21. What is the effect of too much slope?
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed

22. In the GMAW process what does voltage control?
Constant current (CC)
Penetration and burn - off rate of the electrode
Puddle fluidity
If you dont know this check your phone

23. What does the abbreviation NEMA stand for?
To prevent drawing of liquid CO2 (Carbon Dioxide)
When the filler wire is in direct contract with the base metal
SMAW - GTAW
National Electrical Manufactures Association

24. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Generally not as accurate
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity
3

25. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
15 feet (4.5 meters)
85%

26. List 3 forms compressed gases may be supplied for welding
Speed of the feed motor and - starting / stopping electrode feed
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
5.8 to 12.5 L/min

27. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch

28. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Duty cycle

29. 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
Generally not as accurate
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)

30. What type of power source is used with a constant speed wire feeder?
12 to 22 arc volts
Wire feed speed
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat

31. What does voltage do in an electrical circuit?
12 to 22 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gives arc voltage values to the control system of the feeder
Voltage is the force that overcomes resistance to allow amperage flow

32. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Aluminum wire
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Cause flaking - which can clog the liner and contact tube

33. In the GMAW process what does amperage control?
Motor driven generators - Transformer rectifiers - and Inverter designs
Penetration and burn - off rate of the electrode
National Electrical Manufactures Association
Pressure vessels and the piping industry

34. What current and polarity is generally used with GMAW?
Pressure - The rate of flow of a shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
DCEP (Direct Current Electrode Positive) Reverse Polarity

35. Why is a line heater required when using GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas

36. What is the purpose of a regulator and what does it indicate on its gauges?
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity

37. What wire are knurled drive rolls most commonly used on?
Penetration and burn - off rate of the electrode
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires
20 to 200 times per second

38. With straight polarity where is 2/3 of the arc energy?
Guns
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity
The negative side of a welding unit

39. A pull type drive system is usually used on what type of material?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire
Cause flaking - which can clog the liner and contact tube
DCEP (Direct Current Electrode Positive) Reverse Polarity

40. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire
Flux cored wires

41. What is another term for electrode holders for GMAW?
Constant current (CC)
Guns
Voltage is the force that overcomes resistance to allow amperage flow
Short- circuiting transfer - Globular transfer - Spray transfer

42. How are GMAW guns rated?
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas
By there current carrying capacity
Wire feed speed

43. What processes are constant current (CC) power sources designed to be used with?
The resistace to electrical current flow increases with it. Causing the electrode to heat
By there current carrying capacity
SMAW - GTAW
Duty cycle

44. Regulators control_____________ flowmeters SHOW____________.
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
If you dont know this check your phone
Gives arc voltage values to the control system of the feeder

45. List the factors that determine the mode of metal transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

46. What is the recommended electrode stick- out for .035 solid wire?
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
Aluminum wire
To prevent drawing of liquid CO2 (Carbon Dioxide)

47. How many times per second does short circuiting take place?
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
20 to 200 times per second
Penetration and burn - off rate of the electrode

48. What happens when the electrode extension is increased?
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)
Puddle fluidity
Higher 26 to 35 arc volts

49. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Duty cycle
12 to 22 arc volts
The negative side of a welding unit
85%

50. What output on the welding machine is used to rate the duty cycle?
Wire feed speed
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze