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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. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed

2. Regulators control_____________ flowmeters SHOW____________.
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
Flux cored wires
Pressure - The rate of flow of a shielding gas
The Arc voltage

3. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
12 to 22 arc volts

4. List the basic equipment requirements for the GMAW process
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
15 feet (4.5 meters)
Constant voltage (CV)

5. Why is the term GMAW preferred over MIG or MAG?
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
Wire feed speed

6. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

7. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
By there current carrying capacity
Minimum distortion due to low heat input
(DCEP) Direct Current Electrode Positive or Reverse polarity

8. What does the term GMAW identify?
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity
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
Gas metal arc welding

9. Why is globular transfer generally avoided with GMAW?
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer
Spatter problems and poor weld appearance

10. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gives arc voltage values to the control system of the feeder
Reducing the gas source pressure to a constant working pressure

11. What does the wire feeder control?
Gas metal arc welding
Aluminum wire
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
If you dont know this check your phone
The time rate of response for the current rise and fall
Constant voltage (CV)

13. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

14. What controls amperage when using GMAW?
SMAW - GTAW
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure
Wire feed speed

15. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
The Arc voltage

16. What is the recommended electrode stick- out for .035 solid wire?
Pressure - The rate of flow of a shielding gas
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube
1/4 inch to 1/2 inch

17. What type of power source is used with a constant speed wire feeder?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant voltage (CV)

18. What is the disadvantage of the gauge preset type of regulator/flowmeter?
3
Wire feed speed
The negative side of a welding unit
Generally not as accurate

19. List the three methods of metal transfer with GMAW
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit

20. What does inductance control?
By there current carrying capacity
12 to 22 arc volts
SMAW - GTAW
The time rate of response for the current rise and fall

21. In the GMAW process what does voltage control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure
Aluminum wire
Puddle fluidity

22. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed

23. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts

24. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall
Wire feed speed - Voltage control
Duty cycle

25. What is the preferred drive roll design for solid wires?
The resistace to electrical current flow increases with it. Causing the electrode to heat
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove
15 feet (4.5 meters)

26. Why is a fiber washer required and what cylinder gas requires it?
Reducing the gas source pressure to a constant working pressure
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)

27. What current and polarity is generally used with 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)
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity

28. What is a typical flow rate of CO2 for short circuit transfer?
85%
Aluminum wire
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed

29. What is the maximum distance that hard wire can be successfully pushed?
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)
Wire feed speed

30. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

31. What is the key advantage of short circuiting transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association
Minimum distortion due to low heat input
Aluminum wire

32. With straight polarity where is 2/3 of the arc energy?
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
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
Higher 26 to 35 arc volts

33. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association

34. What type of power source is commonly used with a voltage sensing wire feeder?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant current (CC)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer

35. What are the 2 types of wire feeders available?
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
V groove or U groove

36. What is an advantage of pulsed arc transfer with GMAW?
Reducing the gas source pressure to a constant working pressure
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
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

37. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
12 to 22 arc volts
V groove or U groove
15 feet (4.5 meters)

38. What does voltage do in an electrical circuit?
The Arc voltage
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs

39. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

40. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders

41. What is the main purpose of 'slope'?
Constant voltage (CV)
When the filler wire is in direct contract with the base metal
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced

42. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
Short- circuiting transfer - Globular transfer - Spray transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity

43. What is another term for electrode holders for GMAW?
Gives arc voltage values to the control system of the feeder
Guns
Wire feed speed
V groove or U groove

44. A pull type drive system is usually used on what type of material?
SMAW - GTAW
Minimum distortion due to low heat input
Aluminum wire
Cause flaking - which can clog the liner and contact tube

45. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat

46. What is a solenoid valve and what actuates it?
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

47. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Constant current (CC)
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts

48. What 2 organizations designate specifications for GMAW wires?
Higher 26 to 35 arc volts
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
Reducing the gas source pressure to a constant working pressure

49. What 2 controls are found on a GMAW set- up?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed - Voltage control
If you dont know this check your phone

50. What happens when the electrode extension is increased?
12 to 22 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
The resistace to electrical current flow increases with it. Causing the electrode to heat