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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 is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
AWS and CSA
Flux cored wires
The negative side of a welding unit

2. What type of power source is used with a constant speed wire feeder?
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)
AWS and CSA
Shielding the molten weld metal from atmospheric contamination

3. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode

4. What does the abbreviation NEMA stand for?
SMAW - GTAW
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

5. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

6. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
...
Constant voltage (CV)
Higher 26 to 35 arc volts

7. What is a typical flow rate of CO2 for short circuit transfer?
By there current carrying capacity
Minimum distortion due to low heat input
Puddle fluidity
5.8 to 12.5 L/min

8. What is the effect of too much slope?
Gives arc voltage values to the control system of the feeder
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow
Insufficient current to melt the wire off cleanly

9. What does the term GMAW identify?
V groove or U groove
Puddle fluidity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Gas metal arc welding

10. What happens when the electrode extension is increased?
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gives arc voltage values to the control system of the feeder
The resistace to electrical current flow increases with it. Causing the electrode to heat

11. What is the main purpose of 'slope'?
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone
15 feet (4.5 meters)
To limit the short circuiting current so that spatter is reduced

12. What would be an indication that the drive roll pressure is adjusted correctly?
Constant current (CC)
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity

13. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
15 feet (4.5 meters)
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure
...

14. What are the 2 types of wire feeders available?
3
To limit the short circuiting current so that spatter is reduced
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit

15. What is an advantage of pulsed arc transfer with GMAW?
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
DCEP (Direct Current Electrode Positive) Reverse Polarity
3

16. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
3
1/4 inch to 1/2 inch
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

17. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Aluminum wire
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)

18. What is the preferred drive roll design for solid wires?
Insufficient current to melt the wire off cleanly
85%
V groove or U groove
The resistace to electrical current flow increases with it. Causing the electrode to heat

19. Why must CO2 cylinders be used in the vertical position?
...
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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)

20. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
Guns
When the filler wire is in direct contract with the base metal

21. What 2 organizations designate specifications for GMAW wires?
If you dont know this check your phone
AWS and CSA
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

22. What controls the wire speed on a voltage sensing wire feeder?
Duty cycle
Reducing the gas source pressure to a constant working pressure
The Arc voltage
AWS and CSA

23. What current and polarity is generally used with GMAW?
Pressure vessels and the piping industry
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow

24. What is the purpose of the shielding gas used in GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
Speed of the feed motor and - starting / stopping electrode feed
SMAW - GTAW

25. What does a flowmeter do and what does it measure?
The negative side of a welding unit
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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

26. Give a description of 'pinch effect'
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure vessels and the piping industry
3
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

27. What does the wire feeder control?
Insufficient current to melt the wire off cleanly
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
By there current carrying capacity
Speed of the feed motor and - starting / stopping electrode feed

28. List 3 forms compressed gases may be supplied for welding
V groove or U groove
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

29. What does voltage do in an electrical circuit?
Minutes of elapsed time continually run (out of 10 minutes)
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Voltage is the force that overcomes resistance to allow amperage flow
...

30. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch

31. What wire are knurled drive rolls most commonly used on?
Flux cored wires
12 to 22 arc volts
Duty cycle
Speed of the feed motor and - starting / stopping electrode feed

32. What is the purpose of a regulator and what does it indicate on its gauges?
Wire feed speed
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow
Reducing the gas source pressure to a constant working pressure

33. What type of power source is commonly used with a voltage sensing wire feeder?
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW
Constant current (CC)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

34. 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
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

35. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Wire feed speed - Voltage control
Guns
Duty cycle
Constant current (CC)

36. Give a brief description of the GMAW process
Spatter problems and poor weld appearance
Welding process that joins metals by heating them with an electric arc
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)

37. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
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)

38. What is the key advantage of short circuiting transfer?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced

39. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle

40. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
1/4 inch to 1/2 inch
Minimum distortion due to low heat input
3

41. Why is a line heater required when using GMAW?
Puddle fluidity
Gives arc voltage values to the control system of the feeder
Dry ice can form within the flow control openings and cause blockage of shielding gas
...

42. List the three methods of metal transfer with GMAW
V groove or U groove
1/4 inch to 1/2 inch
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW

43. Draw a typical volt amp curve for a machine that is designed for GMAW
Generally not as accurate
If you dont know this check your phone
20 to 200 times per second
Higher 26 to 35 arc volts

44. What is the maximum distance that hard wire can be successfully pushed?
85%
V groove or U groove
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)

45. What controls amperage when using GMAW?
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed
The negative side of a welding unit

46. List several industries that would use GMAW
Pressure vessels and the piping industry
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To limit the short circuiting current so that spatter is reduced

47. 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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts

48. 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
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

49. What is another term for electrode holders for GMAW?
Guns
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer

50. In the GMAW process what does amperage control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Penetration and burn - off rate of the electrode
When the filler wire is in direct contract with the base metal
Pressure - The rate of flow of a shielding gas