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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. When is the metal transferred with short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second
When the filler wire is in direct contract with the base metal
Dry ice can form within the flow control openings and cause blockage of shielding gas

2. What does a flowmeter do and what does it measure?
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

3. Why is the term GMAW preferred over MIG or MAG?
Gas metal arc welding
These terms are quite restrictive and often technically incorrect
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone

4. What is an advantage of pulsed arc transfer with GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Guns
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The negative side of a welding unit

5. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect

6. A 10 minute cycle of welding time vs cooling time a given machine can handle.
These terms are quite restrictive and often technically incorrect
Duty cycle
Pressure - The rate of flow of a 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

7. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Gives arc voltage values to the control system of the feeder

8. How are GMAW guns rated?
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity

9. What processes are constant current (CC) power sources designed to be used with?
Gas metal arc welding
Pressure vessels and the piping industry
Insufficient current to melt the wire off cleanly
SMAW - GTAW

10. Regulators control_____________ flowmeters SHOW____________.
Puddle fluidity
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube

11. List several industries that would use GMAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure vessels and the piping industry
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat

12. Why is a fiber washer required and what cylinder gas requires it?
Voltage is the force that overcomes resistance to allow amperage flow
To prevent leakage - Carbon Dioxide (CO2)
3
...

13. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
National Electrical Manufactures Association
...
V groove or U groove

14. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant voltage (CV)
...
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

15. What is the preferred drive roll design for solid wires?
1/4 inch to 1/2 inch
Gas metal arc welding
V groove or U groove
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

16. Why is a line heater required when using GMAW?
Penetration and burn - off rate of the electrode
Duty cycle
Dry ice can form within the flow control openings and cause blockage of shielding gas
When the filler wire is in direct contract with the base metal

17. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

18. List the three methods of metal transfer with GMAW
Constant current (CC)
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer

19. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Constant current (CC)
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect

20. What is a typical flow rate of CO2 for short circuit transfer?
Constant voltage (CV)
(DCEP) Direct Current Electrode Positive or 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

21. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube
3
Voltage is the force that overcomes resistance to allow amperage flow

22. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Reducing the gas source pressure to a constant working pressure
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

23. Why must CO2 cylinders be used in the vertical position?
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone

24. What is the effect of too much slope?
The Arc voltage
Insufficient current to melt the wire off cleanly
The negative side of a welding unit
When the filler wire is in direct contract with the base metal

25. List the basic equipment requirements for the GMAW process
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

26. What does the term GMAW identify?
85%
Constant current (CC)
Pressure - The rate of flow of a shielding gas
Gas metal arc welding

27. Give a brief description of the GMAW process
3
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
20 to 200 times per second

28. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Spatter problems and poor weld appearance
By there current carrying capacity
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect

29. What type of power source is commonly used with a voltage sensing wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)
Gas metal arc welding
Constant current (CC)

30. With straight polarity where is 2/3 of the arc energy?
Minimum distortion due to low heat input
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The negative side of a welding unit

31. What type of power source is used with a constant speed wire feeder?
Guns
Wire feed speed
Minimum distortion due to low heat input
Constant voltage (CV)

32. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone

33. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed

34. What is another term for electrode holders for GMAW?
Guns
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)
V groove or U groove

35. Give a description of 'pinch effect'
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity

36. What is the recommended electrode stick- out for .035 solid wire?
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
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch

37. What would be an indication that the drive roll pressure is adjusted correctly?
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feeds smoothly (yet will slip should a problem occur in the gun)

38. What is the required arc voltage used for short circuit transfer?
Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)
...
12 to 22 arc volts

39. What is the disadvantage of the gauge preset type of regulator/flowmeter?
If you dont know this check your phone
Wire feed speed
DCEP (Direct Current Electrode Positive) Reverse Polarity
Generally not as accurate

40. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination

41. What does inductance control?
Pressure vessels and the piping industry
The time rate of response for the current rise and fall
Constant current (CC)
Dry ice can form within the flow control openings and cause blockage of shielding gas

42. In the GMAW process what does voltage control?
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
Voltage is the force that overcomes resistance to allow amperage flow
National Electrical Manufactures Association
Puddle fluidity

43. In the GMAW process what does amperage control?
Puddle fluidity
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode

44. List the factors that determine the mode of metal transfer
Reducing the gas source pressure to a constant working pressure
Speed of the feed motor and - starting / stopping electrode feed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
12 to 22 arc volts

45. What is the key advantage of short circuiting transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall
3
Minimum distortion due to low heat input

46. What controls the wire speed on a voltage sensing wire feeder?
National Electrical Manufactures Association
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)

47. 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
15 feet (4.5 meters)
Minimum distortion due to low heat input
When the filler wire is in direct contract with the base metal

48. What wire are knurled drive rolls most commonly used on?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure vessels and the piping industry
15 feet (4.5 meters)
Flux cored wires

49. What is the purpose of a regulator and what does it indicate on its gauges?
The time rate of response for the current rise and fall
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure
When the filler wire is in direct contract with the base metal

50. What controls amperage when using GMAW?
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
Reducing the gas source pressure to a constant working pressure
Wire feed speed