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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. How are GMAW guns rated?
Spatter problems and poor weld appearance
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders

2. List the basic equipment requirements for the GMAW process
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal

3. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Short- circuiting transfer - Globular transfer - Spray transfer
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

4. What does a flowmeter do and what does it measure?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry

5. What controls amperage when using GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed
V groove or U groove
The Arc voltage

6. A pull type drive system is usually used on what type of material?
Aluminum wire
Puddle fluidity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Speed of the feed motor and - starting / stopping electrode feed

7. What is another term for electrode holders for GMAW?
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
National Electrical Manufactures Association

8. What wire are knurled drive rolls most commonly used on?
Guns
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires
Wire feed speed

9. What is the purpose of the shielding gas used in GMAW?
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
DCEP (Direct Current Electrode Positive) Reverse Polarity

10. What does the wire feeder control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow

11. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Puddle fluidity
Aluminum wire
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Constant voltage (CV)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The negative side of a welding unit

13. In the GMAW process what does amperage control?
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure

14. 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
Higher 26 to 35 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts

15. What 2 organizations designate specifications for GMAW wires?
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
Higher 26 to 35 arc volts

16. What type of power source is used with a constant speed wire feeder?
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc
Constant voltage (CV)

17. What is an advantage of pulsed arc transfer with GMAW?
To limit the short circuiting current so that spatter is reduced
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

18. What is the maximum distance that hard wire can be successfully pushed?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure vessels and the piping industry
15 feet (4.5 meters)
Spatter problems and poor weld appearance

19. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Flux cored wires
Pressure vessels and the piping industry
Speed of the feed motor and - starting / stopping electrode feed

20. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure
Constant current (CC)

21. Draw a typical volt amp curve for a machine that is designed for GMAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
Minimum distortion due to low heat input
AWS and CSA

22. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Aluminum wire
If you dont know this check your phone
Constant current (CC)
The resistace to electrical current flow increases with it. Causing the electrode to heat

23. What controls the wire speed on a voltage sensing wire feeder?
Cause flaking - which can clog the liner and contact tube
Constant current (CC)
The Arc voltage
To limit the short circuiting current so that spatter is reduced

24. What is the main purpose of 'slope'?
To prevent drawing of liquid CO2 (Carbon Dioxide)
To limit the short circuiting current so that spatter is reduced
Welding process that joins metals by heating them with an electric arc
Aluminum wire

25. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
The time rate of response for the current rise and fall
V groove or U groove
Higher 26 to 35 arc volts

26. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Controls the rate of flow of a shielding gas to the gun nozzle
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
V groove or U groove

27. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)

28. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat

29. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
AWS and CSA
...
85%

30. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
...
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure - The rate of flow of a shielding gas

31. What happens when the electrode extension is increased?
3
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
The resistace to electrical current flow increases with it. Causing the electrode to heat

32. What is a typical flow rate of CO2 for short circuit transfer?
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)
Guns
5.8 to 12.5 L/min

33. List several industries that would use GMAW
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
By there current carrying capacity

34. What is a solenoid valve and what actuates it?
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
To limit the short circuiting current so that spatter is reduced
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

35. What does inductance control?
The time rate of response for the current rise and fall
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat

36. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

37. What would be an indication that the drive roll pressure is adjusted correctly?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
5.8 to 12.5 L/min
Pressure vessels and the piping industry
Wire feeds smoothly (yet will slip should a problem occur in the gun)

38. What does the term GMAW identify?
Flux cored wires
The Arc voltage
Gas metal arc welding
Spatter problems and poor weld appearance

39. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
SMAW - GTAW
12 to 22 arc volts
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

40. What are the 2 types of wire feeders available?
V groove or U groove
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)

41. Why must CO2 cylinders be used in the vertical position?
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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

42. 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)
National Electrical Manufactures Association
SMAW - GTAW

43. What is the purpose of a regulator and what does it indicate on its gauges?
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure
These terms are quite restrictive and often technically incorrect
Flux cored wires

44. Why is globular transfer generally avoided with GMAW?
Puddle fluidity
20 to 200 times per second
SMAW - GTAW
Spatter problems and poor weld appearance

45. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
5.8 to 12.5 L/min
Higher 26 to 35 arc volts

46. What effect does increasing and decreasing the inductance have on the weld?
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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Generally not as accurate

47. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant voltage (CV)
Duty cycle
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow

48. 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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect

49. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
V groove or U groove

50. What output on the welding machine is used to rate the duty cycle?
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed