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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 type of power source is used with a constant speed wire feeder?
The time rate of response for the current rise and fall
Controls the rate of flow of a shielding gas to the gun nozzle
12 to 22 arc volts
Constant voltage (CV)

2. What effect does increasing and decreasing the inductance have on the weld?
20 to 200 times per second
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
Welding process that joins metals by heating them with an electric arc

3. What is a typical flow rate of CO2 for short circuit transfer?
AWS and CSA
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity

4. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA

5. What does voltage do in an electrical circuit?
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow
Short- circuiting transfer - Globular transfer - Spray transfer
AWS and CSA

6. Why is globular transfer generally avoided with GMAW?
To limit the short circuiting current so that spatter is reduced
Spatter problems and poor weld appearance
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)

7. A pull type drive system is usually used on what type of material?
Aluminum wire
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Motor driven generators - Transformer rectifiers - and Inverter designs

8. What is the main purpose of 'slope'?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Higher 26 to 35 arc volts
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced

9. What is an advantage of pulsed arc transfer with GMAW?
85%
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
SMAW - GTAW

10. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input
1/4 inch to 1/2 inch

11. What output on the welding machine is used to rate the duty cycle?
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)
The time rate of response for the current rise and fall
1/4 inch to 1/2 inch

12. What controls amperage when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry
Shielding the molten weld metal from atmospheric contamination
Wire feed speed

13. What does inductance control?
...
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall
By there current carrying capacity

14. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
V groove or U groove

15. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)

16. What does the abbreviation NEMA stand for?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
National Electrical Manufactures Association

17. How are GMAW guns rated?
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
Higher 26 to 35 arc volts
By there current carrying capacity

18. What happens when the electrode extension is increased?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal

19. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The Arc voltage
3
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone

20. What does the term GMAW identify?
Gas metal arc welding
15 feet (4.5 meters)
By there current carrying capacity
Penetration and burn - off rate of the electrode

21. Why is the term GMAW preferred over MIG or MAG?
Puddle fluidity
Reducing the gas source pressure to a constant working pressure
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube

22. Why must CO2 cylinders be used in the vertical position?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

23. Why is a line heater required when using GMAW?
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Dry ice can form within the flow control openings and cause blockage of shielding gas

24. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure vessels and the piping industry
Higher 26 to 35 arc volts
...

25. What would be an indication that the drive roll pressure is adjusted correctly?
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

26. List the factors that determine the mode of metal transfer
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure - The rate of flow of a shielding gas
Short- circuiting transfer - Globular transfer - Spray transfer

27. What is another term for electrode holders for GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Penetration and burn - off rate of the electrode
By there current carrying capacity
Guns

28. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Cause flaking - which can clog the liner and contact tube
3
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed

29. What 2 controls are found on a GMAW set- up?
...
Wire feed speed - Voltage control
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas

30. What does the wire feeder control?
AWS and CSA
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
3

31. What is the preferred drive roll design for solid wires?
V groove or U groove
Constant voltage (CV)
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
These terms are quite restrictive and often technically incorrect

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

33. What is the maximum distance that hard wire can be successfully pushed?
Duty cycle
Gas metal arc welding
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)

34. What does a flowmeter do and what does it measure?
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
Guns

35. What is the required arc voltage used for short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Aluminum wire
12 to 22 arc volts
To limit the short circuiting current so that spatter is reduced

36. What are the 2 types of wire feeders available?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance
5.8 to 12.5 L/min

37. What is the key advantage of short circuiting transfer?
Puddle fluidity
Minimum distortion due to low heat input
SMAW - GTAW
Constant current (CC)

38. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube

39. What wire are knurled drive rolls most commonly used on?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires
Duty cycle

40. Why is a fiber washer required and what cylinder gas requires it?
Controls the rate of flow of a shielding gas to the gun nozzle
85%
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall

41. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly

42. Give a brief description of the GMAW process
15 feet (4.5 meters)
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
Dry ice can form within the flow control openings and cause blockage of shielding gas

43. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
The negative side of a welding unit

44. What is a solenoid valve and what actuates it?
Gives arc voltage values to the control system of the feeder
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

45. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts

46. A 10 minute cycle of welding time vs cooling time a given machine can handle.
3
Motor driven generators - Transformer rectifiers - and Inverter designs
...
Duty cycle

47. What 2 organizations designate specifications for GMAW wires?
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
3
AWS and CSA

48. Draw a typical volt amp curve for a machine that is designed for GMAW
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
Wire feed speed
Minutes of elapsed time continually run (out of 10 minutes)

49. What type of power source is commonly used with a voltage sensing wire feeder?
The negative side of a welding unit
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant current (CC)

50. List 3 wire drive systems and give a short description of each
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - 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
AWS and CSA