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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. In the GMAW process what does voltage control?
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
Penetration and burn - off rate of the electrode

2. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Constant current (CC)
Constant- speed wire feeders and Voltage- sennsing wire feeders
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

3. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Shielding the molten weld metal from atmospheric contamination
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
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 or Reverse polarity
If you dont know this check your phone

5. What does the wire feeder control?
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
Speed of the feed motor and - starting / stopping electrode feed

6. What is a typical flow rate of CO2 for short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
AWS and CSA
Flux cored wires
5.8 to 12.5 L/min

7. What is another term for electrode holders for GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc
Guns
Puddle fluidity

8. List the three methods of metal transfer with GMAW
15 feet (4.5 meters)
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow

9. What power sources are used with the GMAW Process?
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal

10. Give a description of 'pinch effect'
3
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed

11. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance
Gas metal arc welding
Gives arc voltage values to the control system of the feeder

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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed - Voltage control
Voltage is the force that overcomes resistance to allow amperage flow

13. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Duty cycle
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts

14. What is the key advantage of short circuiting transfer?
These terms are quite restrictive and often technically incorrect
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input
When the filler wire is in direct contract with the base metal

15. What 2 organizations designate specifications for GMAW wires?
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input
AWS and CSA
Welding process that joins metals by heating them with an electric arc

16. Why is globular transfer generally avoided with GMAW?
Reducing the gas source pressure to a constant working pressure
DCEP (Direct Current Electrode Positive) Reverse Polarity
Spatter problems and poor weld appearance
Wire feed speed

17. What is a solenoid valve and what actuates it?
(DCEP) Direct Current Electrode Positive or Reverse polarity
The Arc voltage
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

18. What current and polarity is generally used with GMAW?
...
Controls the rate of flow of a shielding gas to the gun nozzle
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity

19. Why is the term GMAW preferred over MIG or MAG?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant voltage (CV)
These terms are quite restrictive and often technically incorrect
Gas metal arc welding

20. With straight polarity where is 2/3 of the arc energy?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Penetration and burn - off rate of the electrode
Gas metal arc welding
The negative side of a welding unit

21. What controls amperage when using GMAW?
20 to 200 times per second
Puddle fluidity
Wire feed speed
15 feet (4.5 meters)

22. Why must CO2 cylinders be used in the vertical position?
Higher 26 to 35 arc volts
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone

23. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Duty cycle
...
Constant- speed wire feeders and Voltage- sennsing wire feeders

24. What is the purpose of the shielding gas used in GMAW?
Wire feed speed
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination

25. List several industries that would use GMAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on 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
85%
Pressure vessels and the piping industry

26. What does the abbreviation NEMA stand for?
The negative side of a welding unit
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube

27. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Reducing the gas source pressure to a constant working pressure
The resistace to electrical current flow increases with it. Causing the electrode to heat
To limit the short circuiting current so that spatter is reduced

28. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
3
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

29. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
When the filler wire is in direct contract with the base metal
...
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs

30. What wire are knurled drive rolls most commonly used on?
The Arc voltage
Flux cored wires
12 to 22 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

31. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
AWS and CSA

32. What is the recommended electrode stick- out for .035 solid wire?
Shielding the molten weld metal from atmospheric contamination
The Arc voltage
1/4 inch to 1/2 inch
National Electrical Manufactures Association

33. List 3 forms compressed gases may be supplied for welding
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts
Aluminum wire

34. What happens when the electrode extension is increased?
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

35. When is the metal transferred with short circuit transfer?
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
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal

36. What does inductance control?
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)
The time rate of response for the current rise and fall
Puddle fluidity

37. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Shielding the molten weld metal from atmospheric contamination
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min

38. List 3 wire drive systems and give a short description of each
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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
AWS and CSA
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

39. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
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
5.8 to 12.5 L/min
Gas metal arc welding

40. What is the effect of too much slope?
AWS and CSA
If you dont know this check your phone
Insufficient current to melt the wire off cleanly
Flux cored wires

41. What effect does increasing and decreasing the inductance have on the weld?
12 to 22 arc volts
Higher 26 to 35 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Aluminum wire

42. What are the 2 types of wire feeders available?
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
Flux cored wires
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

43. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs

44. Why is a line heater required when using GMAW?
The time rate of response for the current rise and fall
Duty cycle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Dry ice can form within the flow control openings and cause blockage of shielding gas

45. What 2 controls are found on a GMAW set- up?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Wire feed speed - Voltage control

46. What output on the welding machine is used to rate the duty cycle?
The Arc voltage
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity
Constant- speed wire feeders and Voltage- sennsing wire feeders

47. What does the term GMAW identify?
Spatter problems and poor weld appearance
Gas metal arc welding
85%
Speed of the feed motor and - starting / stopping electrode feed

48. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
3

49. What is the preferred drive roll design for solid wires?
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
National Electrical Manufactures Association

50. What controls the wire speed on a voltage sensing wire feeder?
Wire feed speed - Voltage control
The Arc voltage
V groove or U groove
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field