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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. A pull type drive system is usually used on what type of material?
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
Aluminum wire
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

2. What is the effect of too much slope?
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
Spatter problems and poor weld appearance
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control

3. What does the wire feeder control?
3
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas

4. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Spatter problems and poor weld appearance
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

5. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
When the filler wire is in direct contract with the base metal
Constant voltage (CV)
Higher 26 to 35 arc volts
...

6. What are the 2 types of wire feeders available?
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders
1/4 inch to 1/2 inch
Pressure - The rate of flow of a shielding gas

7. When is the metal transferred with short circuit transfer?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Short- circuiting transfer - Globular transfer - Spray transfer
When the filler wire is in direct contract with the base metal
Motor driven generators - Transformer rectifiers - and Inverter designs

8. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
Voltage is the force that overcomes resistance to allow amperage flow

9. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Gives arc voltage values to the control system of the feeder
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
3

10. What output on the welding machine is used to rate the duty cycle?
Flux cored wires
Gas metal arc welding
Minutes of elapsed time continually run (out of 10 minutes)
Constant current (CC)

11. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Insufficient current to melt the wire off cleanly
Duty cycle
These terms are quite restrictive and often technically incorrect
AWS and CSA

12. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Controls the rate of flow of a shielding gas to the gun nozzle
Gives arc voltage values to the control system of the feeder

13. In the GMAW process what does voltage control?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity

14. What is the purpose of the shielding gas used in GMAW?
The time rate of response for the current rise and fall
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...
Shielding the molten weld metal from atmospheric contamination

15. What happens when the electrode extension is increased?
By there current carrying capacity
Penetration and burn - off rate of the electrode
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

16. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
When the filler wire is in direct contract with the base metal
Short- circuiting transfer - Globular transfer - Spray transfer
National Electrical Manufactures Association

17. What 2 controls are found on a GMAW set- up?
Minimum distortion due to low heat input
Wire feed speed - Voltage control
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)

18. List 3 wire drive systems and give a short description of each
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
If you dont know this check your phone
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

19. List several industries that would use GMAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure vessels and the piping industry
V groove or U groove
Puddle fluidity

20. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

21. Why is the term GMAW preferred over MIG or MAG?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
These terms are quite restrictive and often technically incorrect
85%
When the filler wire is in direct contract with the base metal

22. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
SMAW - GTAW
Gives arc voltage values to the control system of the feeder

23. List the basic equipment requirements for the GMAW process
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Shielding the molten weld metal from atmospheric contamination

24. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association
Spatter problems and poor weld appearance
20 to 200 times per second

25. How are GMAW guns rated?
V groove or U groove
12 to 22 arc volts
5.8 to 12.5 L/min
By there current carrying capacity

26. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity
Aluminum wire

27. With straight polarity where is 2/3 of the arc energy?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
3
Gives arc voltage values to the control system of the feeder
The negative side of a welding unit

28. What controls amperage when using GMAW?
Wire feed speed
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle
Pressure - The rate of flow of a shielding gas

29. 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
Wire feed speed
To prevent drawing of liquid CO2 (Carbon Dioxide)
To limit the short circuiting current so that spatter is reduced

30. What effect does increasing and decreasing the inductance have on the weld?
V groove or U groove
15 feet (4.5 meters)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant current (CC)

31. What type of power source is used with a constant speed wire feeder?
Spatter problems and poor weld appearance
Constant voltage (CV)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed

32. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
85%
By there current carrying capacity
Gas metal arc welding

33. What is the key advantage of short circuiting 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
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
Minimum distortion due to low heat input

34. What does the term GMAW identify?
Constant current (CC)
Gas metal arc welding
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feed speed - Voltage control

35. Regulators control_____________ flowmeters SHOW____________.
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a shielding gas
Aluminum wire
When the filler wire is in direct contract with the base metal

36. 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)
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
(DCEP) Direct Current Electrode Positive or Reverse polarity

37. What is the preferred drive roll design for solid wires?
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed

38. What is a solenoid valve and what actuates it?
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
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc

39. Why must CO2 cylinders be used in the vertical position?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch

40. Why is a fiber washer required and what cylinder gas requires it?
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs

41. What does the abbreviation NEMA stand for?
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA
National Electrical Manufactures Association
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

42. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a shielding gas
National Electrical Manufactures Association

43. What is another term for electrode holders for GMAW?
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly
Guns
SMAW - GTAW

44. Draw a typical volt amp curve for a machine that is designed for GMAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
SMAW - GTAW
If you dont know this check your phone
Flux cored wires

45. What power sources are used with the GMAW Process?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gives arc voltage values to the control system of the feeder
Motor driven generators - Transformer rectifiers - and Inverter designs

46. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
Motor driven generators - Transformer rectifiers - and Inverter designs

47. What is a typical flow rate of CO2 for short circuit transfer?
Wire feed speed
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

48. Why is a line heater required when using GMAW?
Constant voltage (CV)
15 feet (4.5 meters)
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove

49. What does voltage do in an electrical circuit?
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

50. List the three methods of metal transfer with GMAW
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Short- circuiting transfer - Globular transfer - Spray transfer