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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 effect does increasing and decreasing the inductance have on the weld?
Wire feed speed
Reducing the gas source pressure to a constant working pressure
V groove or U groove
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

2. What would be an indication that the drive roll pressure is adjusted correctly?
Shielding the molten weld metal from atmospheric contamination
Wire feeds smoothly (yet will slip should a problem occur in the gun)
5.8 to 12.5 L/min
If you dont know this check your phone

3. What is the purpose of the shielding gas used in GMAW?
Welding process that joins metals by heating them with an electric arc
To prevent drawing of liquid CO2 (Carbon Dioxide)
By there current carrying capacity
Shielding the molten weld metal from atmospheric contamination

4. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Flux cored wires
Aluminum wire
Wire feed speed

5. In the GMAW process what does amperage control?
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode
SMAW - GTAW
(DCEP) Direct Current Electrode Positive or Reverse polarity

6. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Pressure vessels and the piping industry
3
Minimum distortion due to low heat input

7. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
V groove or U groove
...
To limit the short circuiting current so that spatter is reduced

8. Why is a line heater required when using GMAW?
These terms are quite restrictive and often technically incorrect
Aluminum wire
5.8 to 12.5 L/min
Dry ice can form within the flow control openings and cause blockage of shielding gas

9. Why is the term GMAW preferred over MIG or MAG?
Higher 26 to 35 arc volts
Wire feed speed
These terms are quite restrictive and often technically incorrect
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

10. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
The resistace to electrical current flow increases with it. Causing the electrode to heat
1/4 inch to 1/2 inch
The negative side of a welding unit

11. Give a description of 'pinch effect'
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Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Motor driven generators - Transformer rectifiers - and Inverter designs

12. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Higher 26 to 35 arc volts

13. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Guns
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
1/4 inch to 1/2 inch

14. What current and polarity is generally used with GMAW?
By there current carrying capacity
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow

15. What is the main purpose of 'slope'?
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Reducing the gas source pressure to a constant working pressure

16. Give a brief description of the GMAW process
National Electrical Manufactures Association
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc

17. List several industries that would use GMAW
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry
85%

18. What is the effect of too much slope?
20 to 200 times per second
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
Wire feed speed

19. Draw a typical volt amp curve for a machine that is designed for GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Reducing the gas source pressure to a constant working pressure

20. What is the key advantage of short circuiting transfer?
Wire feed speed
Minimum distortion due to low heat input
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow

21. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
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
Wire feed speed - Voltage control

22. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Higher 26 to 35 arc volts
If you dont know this check your phone
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect

23. Why is a fiber washer required and what cylinder gas requires it?
Cause flaking - which can clog the liner and contact tube
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
To prevent leakage - Carbon Dioxide (CO2)

24. What is the purpose of a regulator and what does it indicate on its gauges?
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
Guns
Higher 26 to 35 arc volts

25. What does the term GMAW identify?
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove

26. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Reducing the gas source pressure to a constant working pressure
Constant current (CC)
The Arc voltage

27. What does the abbreviation NEMA stand for?
Pressure vessels and the piping industry
National Electrical Manufactures Association
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)

28. 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
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity

29. What is another term for electrode holders for GMAW?
12 to 22 arc volts
Guns
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode
Generally not as accurate
12 to 22 arc volts

31. List the factors that determine the mode of metal transfer
Pressure vessels and the piping industry
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant current (CC)
Speed of the feed motor and - starting / stopping electrode feed

32. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association
Wire feed speed - Voltage control

33. A pull type drive system is usually used on what type of material?
To limit the short circuiting current so that spatter is reduced
Aluminum wire
The resistace to electrical current flow increases with it. Causing the electrode to heat
Insufficient current to melt the wire off cleanly

34. 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
5.8 to 12.5 L/min
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

35. List 3 wire drive systems and give a short description of each
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
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
If you dont know this check your phone

36. What is a solenoid valve and what actuates it?
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

37. What controls amperage when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Short- circuiting transfer - Globular transfer - Spray transfer

38. What does the wire feeder control?
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
Speed of the feed motor and - starting / stopping electrode feed
The negative side of a welding unit

39. What is an advantage of pulsed arc transfer with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
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
Higher 26 to 35 arc volts

40. What processes are constant current (CC) power sources designed to be used with?
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

41. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Insufficient current to melt the wire off cleanly
Puddle fluidity

42. What does voltage do in an electrical circuit?
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow
Constant current (CC)
Constant- speed wire feeders and Voltage- sennsing wire feeders

43. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
V groove or U groove
...
5.8 to 12.5 L/min

44. List the basic equipment requirements for the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

45. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Wire feed speed - Voltage control
The time rate of response for the current rise and fall
Short- circuiting transfer - Globular transfer - Spray transfer

46. What is a typical flow rate of CO2 for short circuit transfer?
Constant voltage (CV)
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min

47. How are GMAW guns rated?
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
By there current carrying capacity

48. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Generally not as accurate
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The resistace to electrical current flow increases with it. Causing the electrode to heat

49. 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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Short- circuiting transfer - Globular transfer - Spray transfer

50. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone