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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. 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
...
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%

2. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Gas metal arc welding
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle

3. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
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
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat

4. What is the disadvantage of the gauge preset type of regulator/flowmeter?
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. What does the term GMAW identify?
Welding process that joins metals by heating them with an electric arc
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination
Gas metal arc welding

6. What is the effect of too much slope?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs

7. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts

8. 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
Gives arc voltage values to the control system of the feeder
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect

9. What type of power source is commonly used with a voltage sensing wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding
Constant current (CC)
The Arc voltage

10. What does a flowmeter do and what does it measure?
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
When the filler wire is in direct contract with the base metal

11. What is the preferred drive roll design for solid wires?
When the filler wire is in direct contract with the base metal
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

12. What controls amperage when using GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association

13. List 3 forms compressed gases may be supplied for welding
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding

14. What is the purpose of the shielding gas used in GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed

15. What does the wire feeder control?
To prevent leakage - Carbon Dioxide (CO2)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed

16. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Spatter problems and poor weld appearance
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To limit the short circuiting current so that spatter is reduced

17. Draw a typical volt amp curve for a machine that is designed for GMAW
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85%
Shielding the molten weld metal from atmospheric contamination
...

18. Give a description of 'pinch effect'
Guns
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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

19. With straight polarity where is 2/3 of the arc energy?
Welding process that joins metals by heating them with an electric arc
Constant current (CC)
The negative side of a welding unit
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

20. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity

21. List several industries that would use GMAW
Puddle fluidity
Wire feed speed - Voltage control
Pressure vessels and the piping industry
12 to 22 arc volts

22. What does inductance control?
Spatter problems and poor weld appearance
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
The time rate of response for the current rise and fall

23. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube

24. List the factors that determine the mode of metal transfer
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Generally not as accurate

25. What current and polarity is generally used with GMAW?
1/4 inch to 1/2 inch
85%
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas

26. What wire are knurled drive rolls most commonly used on?
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
Pressure - The rate of flow of a shielding gas

27. What is the maximum distance that hard wire can be successfully pushed?
Minimum distortion due to low heat input
By there current carrying capacity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
15 feet (4.5 meters)

28. What effect does increasing and decreasing the inductance have on the weld?
The Arc voltage
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The negative side of a welding unit
Flux cored wires

30. Why is the term GMAW preferred over MIG or MAG?
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

31. What does the abbreviation NEMA stand for?
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association
Duty cycle
AWS and CSA

32. In the GMAW process what does voltage control?
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 time rate of response for the current rise and fall
Puddle fluidity

33. How are GMAW guns rated?
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube
AWS and CSA
By there current carrying capacity

34. List the basic equipment requirements for the GMAW process
Aluminum wire
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

35. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Welding process that joins metals by heating them with an electric arc
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
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder
...
Cause flaking - which can clog the liner and contact tube

37. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

38. What is a typical flow rate of CO2 for short circuit transfer?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
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

39. List the three methods of metal transfer with GMAW
Minimum distortion due to low heat input
5.8 to 12.5 L/min
Motor driven generators - Transformer rectifiers - and Inverter designs
Short- circuiting transfer - Globular transfer - Spray transfer

40. What output on the welding machine is used to rate the duty cycle?
Generally not as accurate
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas

41. What type of power source is used with a constant speed wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Guns
Constant voltage (CV)
Spatter problems and poor weld appearance

42. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders

43. What are the 2 types of wire feeders available?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed
When the filler wire is in direct contract with the base metal

44. What is another term for electrode holders for GMAW?
...
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Guns
12 to 22 arc volts

45. In the GMAW process what does amperage control?
By there current carrying capacity
Penetration and burn - off rate of the electrode
The negative side of a welding unit
3

46. What processes are constant current (CC) power sources designed to be used with?
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW
Generally not as accurate

47. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced
Flux cored wires
3

48. Regulators control_____________ flowmeters SHOW____________.
V groove or U groove
Aluminum wire
Pressure - The rate of flow of a shielding gas
The Arc voltage

49. 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
Short- circuiting transfer - Globular transfer - Spray transfer
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance

50. A pull type drive system is usually used on what type of material?
Aluminum wire
Minimum distortion due to low heat input
National Electrical Manufactures Association
Generally not as accurate