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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 term is used to describe when the workpiece is hooked to the negative pole on the power source?
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
(DCEP) Direct Current Electrode Positive or Reverse polarity

2. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Guns
15 feet (4.5 meters)
Aluminum wire

3. In the GMAW process what does amperage control?
Cause flaking - which can clog the liner and contact tube
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
AWS and CSA

4. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Generally not as accurate
Wire feed speed
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. Why is a line heater required when using GMAW?
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode
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

6. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly

7. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
15 feet (4.5 meters)
Aluminum wire
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

8. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder
Wire feed speed
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9. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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
...
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10. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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National Electrical Manufactures Association
1/4 inch to 1/2 inch
Guns

11. 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)
12 to 22 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders

12. What does a flowmeter do and what does it measure?
5.8 to 12.5 L/min
Controls the rate of flow of a shielding gas to the gun nozzle
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)

13. 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
Voltage is the force that overcomes resistance to allow amperage flow
Welding process that joins metals by heating them with an electric arc
Pressure vessels and the piping industry

14. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)
Generally not as accurate
Higher 26 to 35 arc volts

15. What is the required arc voltage used for short circuit transfer?
Generally not as accurate
Higher 26 to 35 arc volts
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

16. What are the 2 types of wire feeders available?
These terms are quite restrictive and often technically incorrect
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
Constant- speed wire feeders and Voltage- sennsing wire feeders

17. What output on the welding machine is used to rate the duty cycle?
Guns
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)

18. What is the key advantage of short circuiting transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
5.8 to 12.5 L/min

19. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Short- circuiting transfer - Globular transfer - Spray transfer
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination

20. What is a typical flow rate of CO2 for short circuit transfer?
Duty cycle
Controls the rate of flow of a shielding gas to the gun nozzle
The time rate of response for the current rise and fall
5.8 to 12.5 L/min

21. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure vessels and the piping industry
Wire feed speed
Minimum distortion due to low heat input

22. What type of power source is used with a constant speed wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant current (CC)
Constant voltage (CV)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

23. How many times per second does short circuiting take place?
20 to 200 times per second
Aluminum wire
The Arc voltage
1/4 inch to 1/2 inch

24. What happens when the electrode extension is increased?
85%
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure vessels and the piping industry

25. What does inductance control?
Duty cycle
The time rate of response for the current rise and fall
Gas metal arc welding
AWS and CSA

26. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle

27. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)
Aluminum wire
Wire feed speed - Voltage control

28. List the three methods of metal transfer with GMAW
15 feet (4.5 meters)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer

29. What is another term for electrode holders for GMAW?
Guns
Higher 26 to 35 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
3

30. What is the effect of too much slope?
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly

31. In the GMAW process what does voltage control?
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity

32. Give a description of 'pinch effect'
Puddle fluidity
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Shielding the molten weld metal from atmospheric contamination

33. What is the purpose of the shielding gas used in GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

34. What does the term GMAW identify?
20 to 200 times per second
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding

35. What wire are knurled drive rolls most commonly used on?
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity
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Flux cored wires

36. List several industries that would use GMAW
Guns
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure vessels and the piping industry

37. What is the preferred drive roll design for solid wires?
V groove or U groove
Wire feed speed - Voltage control
Reducing the gas source pressure to a constant working pressure
85%

38. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
20 to 200 times per second
Spatter problems and poor weld appearance
Cause flaking - which can clog the liner and contact tube

39. What is the main purpose of 'slope'?
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)

40. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)

41. What does the wire feeder control?
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode

42. What effect does increasing and decreasing the inductance have on the weld?
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect

43. What 2 controls are found on a GMAW set- up?
85%
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat

44. What controls amperage when using GMAW?
Higher 26 to 35 arc volts
Wire feed speed
15 feet (4.5 meters)
Controls the rate of flow of a shielding gas to the gun nozzle

45. What does the abbreviation NEMA stand for?
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal
National Electrical Manufactures Association

46. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Reducing the gas source pressure to a constant working pressure
Generally not as accurate
To limit the short circuiting current so that spatter is reduced
Guns

47. Why is the term GMAW preferred over MIG or MAG?
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
SMAW - GTAW
These terms are quite restrictive and often technically incorrect

48. Why is a fiber washer required and what cylinder gas requires it?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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49. What is the maximum distance that hard wire can be successfully pushed?
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
12 to 22 arc volts

50. List the basic equipment requirements for the GMAW process
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Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Wire feed speed