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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. List the factors that determine the mode of metal transfer
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

2. A 10 minute cycle of welding time vs cooling time a given machine can handle.
V groove or U groove
Puddle fluidity
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle

3. What is the maximum distance that hard wire can be successfully pushed?
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
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Guns
Reducing the gas source pressure to a constant working pressure
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

5. What are the 2 types of wire feeders available?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding

6. What is another term for electrode holders for GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
Higher 26 to 35 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

7. 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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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

8. What would be an indication that the drive roll pressure is adjusted correctly?
Shielding the molten weld metal from atmospheric contamination
These terms are quite restrictive and often technically incorrect
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)

9. Why is the term GMAW preferred over MIG or MAG?
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

10. What is an advantage of pulsed arc transfer with GMAW?
Gives arc voltage values to the control system of the feeder
Minutes of elapsed time continually run (out of 10 minutes)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Controls the rate of flow of a shielding gas to the gun nozzle

11. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination
V groove or U groove
DCEP (Direct Current Electrode Positive) Reverse Polarity

12. List 3 forms compressed gases may be supplied for welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gas metal arc welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

13. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Cause flaking - which can clog the liner and contact tube
Aluminum wire

14. What is the main purpose of 'slope'?
Generally not as accurate
Welding process that joins metals by heating them with an electric arc
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced

15. Why must CO2 cylinders be used in the vertical position?
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)

16. 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
Gas metal arc welding
Spatter problems and poor weld appearance
Shielding the molten weld metal from atmospheric contamination

17. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Minimum distortion due to low heat input
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

18. List the basic equipment requirements for the GMAW process
Spatter problems and poor weld appearance
Welding process that joins metals by heating them with an electric arc
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

19. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
15 feet (4.5 meters)
Wire feed speed
To limit the short circuiting current so that spatter is reduced

20. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate

21. What 2 organizations designate specifications for GMAW wires?
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
AWS and CSA
1/4 inch to 1/2 inch

22. Regulators control_____________ flowmeters SHOW____________.
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage

23. What 2 controls are found on a GMAW set- up?
Insufficient current to melt the wire off cleanly
85%
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control

24. What is the purpose of the shielding gas used in 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
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone

25. What is the preferred drive roll design for solid wires?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts
V groove or U groove

26. Why is a fiber washer required and what cylinder gas requires it?
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced

27. Give a brief description of the GMAW process
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

28. What happens when the electrode extension is increased?
Wire feed speed
Gives arc voltage values to the control system of the feeder
Speed of the feed motor and - starting / stopping electrode feed
The resistace to electrical current flow increases with it. Causing the electrode to heat

29. What processes are constant current (CC) power sources designed to be used with?
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
SMAW - GTAW
5.8 to 12.5 L/min

30. What controls amperage when using GMAW?
If you dont know this check your phone
Penetration and burn - off rate of the electrode
Wire feed speed
Aluminum wire

31. What does voltage do in an electrical circuit?
20 to 200 times per second
Flux cored wires
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

32. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Wire feed speed - Voltage control
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity

33. What is the effect of too much slope?
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
1/4 inch to 1/2 inch
20 to 200 times per second

34. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity
Gas metal arc welding
85%

35. What is a typical flow rate of CO2 for short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
5.8 to 12.5 L/min
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. What power sources are used with the GMAW Process?
Speed of the feed motor and - starting / stopping electrode feed
Motor driven generators - Transformer rectifiers - and Inverter designs
By there current carrying capacity
Duty cycle

37. Why is globular transfer generally avoided with GMAW?
If you dont know this check your phone
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
20 to 200 times per second

38. What current and polarity is generally used with GMAW?
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity

39. What does inductance control?
The time rate of response for the current rise and fall
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
The resistace to electrical current flow increases with it. Causing the electrode to heat

40. A pull type drive system is usually used on what type of material?
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs

41. List 3 wire drive systems and give a short description of each
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
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

42. List several industries that would use GMAW
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire
The resistace to electrical current flow increases with it. Causing the electrode to heat

43. How are GMAW guns rated?
Reducing the gas source pressure to a constant working pressure
Penetration and burn - off rate of the electrode
By there current carrying capacity
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

44. What does a flowmeter do and what does it measure?
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle

45. In the GMAW process what does amperage control?
...
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control
Duty cycle

46. What is the key advantage of short circuiting transfer?
Shielding the molten weld metal from atmospheric contamination
Minimum distortion due to low heat input
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)

47. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

48. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle
Higher 26 to 35 arc volts
85%

49. What does the abbreviation NEMA stand for?
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association
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

50. What does the wire feeder control?
20 to 200 times per second
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect