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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 must CO2 cylinders be used in the vertical position?
Spatter problems and poor weld appearance
To prevent drawing of liquid CO2 (Carbon Dioxide)
Insufficient current to melt the wire off cleanly
Constant voltage (CV)

2. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Generally not as accurate

3. What does the abbreviation NEMA stand for?
Spatter problems and poor weld appearance
National Electrical Manufactures Association
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant voltage (CV)

4. Give a brief description of the GMAW process
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
Constant voltage (CV)
By there current carrying capacity

5. Give a description of 'pinch effect'
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
These terms are quite restrictive and often technically incorrect
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

6. What type of power source is used with a constant speed wire feeder?
85%
Constant voltage (CV)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

7. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder

8. What is the key advantage of short circuiting transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Minimum distortion due to low heat input
Flux cored wires
Insufficient current to melt the wire off cleanly

9. What is the maximum distance that hard wire can be successfully pushed?
3
5.8 to 12.5 L/min
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)

10. List several industries that would use GMAW
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feeds smoothly (yet will slip should a problem occur in the gun)

11. What happens when the electrode extension is increased?
To prevent drawing of liquid CO2 (Carbon Dioxide)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Motor driven generators - Transformer rectifiers - and Inverter designs

12. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

13. What is a solenoid valve and what actuates it?
The negative side of a welding unit
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
20 to 200 times per second

14. List the basic equipment requirements for the GMAW process
Flux cored wires
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

15. What wire are knurled drive rolls most commonly used on?
Insufficient current to melt the wire off cleanly
By there current carrying capacity
3
Flux cored wires

16. What is the recommended electrode stick- out for .035 solid wire?
By there current carrying capacity
20 to 200 times per second
1/4 inch to 1/2 inch
AWS and CSA

17. Why is a line heater required when using GMAW?
Aluminum wire
3
20 to 200 times per second
Dry ice can form within the flow control openings and cause blockage of shielding gas

18. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
DCEP (Direct Current Electrode Positive) Reverse Polarity
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

19. What controls amperage when using GMAW?
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed

20. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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
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

21. What does a flowmeter do and what does it measure?
Aluminum wire
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders

22. List 3 forms compressed gases may be supplied for welding
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

23. What is the preferred drive roll design for solid wires?
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
V groove or U groove
Puddle fluidity

24. What is the purpose of a regulator and what does it indicate on its gauges?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Reducing the gas source pressure to a constant working pressure
Gas metal arc welding
The Arc voltage

25. List the factors that determine the mode of metal transfer
15 feet (4.5 meters)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

26. What does voltage do in an electrical circuit?
...
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow

27. When is the metal transferred with short circuit transfer?
Constant current (CC)
When the filler wire is in direct contract with the base metal
The time rate of response for the current rise and fall
SMAW - GTAW

28. In the GMAW process what does amperage control?
The time rate of response for the current rise and fall
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
Penetration and burn - off rate of the electrode
Aluminum wire

29. What is another term for electrode holders for GMAW?
...
Guns
Gives arc voltage values to the control system of the feeder
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

30. How many times per second does short circuiting take place?
20 to 200 times per second
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)

31. What output on the welding machine is used to rate the duty cycle?
The Arc voltage
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
12 to 22 arc volts

32. What controls the wire speed on a voltage sensing wire feeder?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage
Generally not as accurate
Dry ice can form within the flow control openings and cause blockage of shielding gas

33. List 3 wire drive systems and give a short description of each
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder
Minutes of elapsed time continually run (out of 10 minutes)
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

34. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
20 to 200 times per second

35. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
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
85%

36. In the GMAW process what does voltage control?
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity

37. What 2 organizations designate specifications for GMAW wires?
Minimum distortion due to low heat input
AWS and CSA
Constant voltage (CV)
...

38. What processes are constant current (CC) power sources designed to be used with?
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
SMAW - GTAW

39. What are the 2 types of wire feeders available?
Generally not as accurate
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect

40. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders

41. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas
15 feet (4.5 meters)

42. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Insufficient current to melt the wire off cleanly
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity

43. Why is a fiber washer required and what cylinder gas requires it?
...
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)

44. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
(DCEP) Direct Current Electrode Positive or Reverse polarity
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

45. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires
The Arc voltage
Pressure vessels and the piping industry

46. What would be an indication that the drive roll pressure is adjusted correctly?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)

47. List the three methods of metal transfer with GMAW
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer

48. What is an advantage of pulsed arc transfer with GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
5.8 to 12.5 L/min
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

49. Why is the term GMAW preferred over MIG or MAG?
Generally not as accurate
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
SMAW - GTAW

50. What is the main purpose of 'slope'?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc