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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. What controls the wire speed on a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires

2. When is the metal transferred with short circuit transfer?
These terms are quite restrictive and often technically incorrect
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
When the filler wire is in direct contract with the base metal

3. Why is globular transfer generally avoided with GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance
Short- circuiting transfer - Globular transfer - Spray transfer
Penetration and burn - off rate of the electrode

4. A pull type drive system is usually used on what type of material?
The time rate of response for the current rise and fall
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Aluminum wire

5. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control
The negative side of a welding unit

6. Regulators control_____________ flowmeters SHOW____________.
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas

7. What happens when the electrode extension is increased?
Gives arc voltage values to the control system of the feeder
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The resistace to electrical current flow increases with it. Causing the electrode to heat
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

8. What is another term for electrode holders for GMAW?
Guns
Gas metal arc welding
...
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

9. What effect does increasing and decreasing the inductance have on the weld?
Pressure vessels and the piping industry
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 Arc voltage
To prevent leakage - Carbon Dioxide (CO2)

10. In the GMAW process what does voltage control?
Puddle fluidity
12 to 22 arc volts
Wire feed speed
85%

11. What does the term GMAW identify?
Gas metal arc welding
If you dont know this check your phone
Puddle fluidity
National Electrical Manufactures Association

12. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA

13. What does inductance control?
Shielding the molten weld metal from atmospheric contamination
The time rate of response for the current rise and fall
Gives arc voltage values to the control system of the feeder
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

14. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Cause flaking - which can clog the liner and contact tube
The Arc voltage
Gives arc voltage values to the control system of the feeder

15. What current and polarity is generally used with GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)

16. What is the effect of too much slope?
...
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
Insufficient current to melt the wire off cleanly

17. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
These terms are quite restrictive and often technically incorrect
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
V groove or U groove

18. What output on the welding machine is used to rate the duty cycle?
By there current carrying capacity
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer

19. What is the purpose of a regulator and what does it indicate on its gauges?
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure
Constant current (CC)
To prevent leakage - Carbon Dioxide (CO2)

20. How many times per second does short circuiting take place?
20 to 200 times per second
Pressure - The rate of flow of a shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
Dry ice can form within the flow control openings and cause blockage of shielding gas

21. What wire are knurled drive rolls most commonly used on?
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires
The negative side of a welding unit

22. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
The Arc voltage
Shielding the molten weld metal from atmospheric contamination

23. What type of power source is commonly used with a voltage sensing wire feeder?
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires
Constant current (CC)

24. In the GMAW process what does amperage control?
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)

25. What power sources are used with the GMAW Process?
3
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
By there current carrying capacity

26. What is the maximum distance that hard wire can be successfully pushed?
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
15 feet (4.5 meters)
5.8 to 12.5 L/min

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

28. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
By there current carrying capacity
1/4 inch to 1/2 inch
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer

29. What type of power source is used with a constant speed wire feeder?
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
By there current carrying capacity
Constant voltage (CV)

30. What would be an indication that the drive roll pressure is adjusted correctly?
AWS and CSA
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)

31. What is the required arc voltage used for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Minimum distortion due to low heat input
Wire feed speed - Voltage control

32. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
3
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode

33. What controls amperage when using GMAW?
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant voltage (CV)
DCEP (Direct Current Electrode Positive) Reverse Polarity

34. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
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
Motor driven generators - Transformer rectifiers - and Inverter designs

35. What is the recommended electrode stick- out for .035 solid wire?
When the filler wire is in direct contract with the base metal
1/4 inch to 1/2 inch
Flux cored wires
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. What does a flowmeter do and what does it measure?
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)
When the filler wire is in direct contract with the base metal

37. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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

38. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
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

39. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
Insufficient current to melt the wire off cleanly

40. How are GMAW guns rated?
Wire feed speed - Voltage control
By there current carrying capacity
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch

41. Why is a fiber washer required and what cylinder gas requires it?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent leakage - Carbon Dioxide (CO2)
Pressure vessels and the piping industry
The time rate of response for the current rise and fall

42. What 2 organizations designate specifications for GMAW wires?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant current (CC)
AWS and CSA
Pressure vessels and the piping industry

43. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
Gives arc voltage values to the control system of the feeder
Dry ice can form within the flow control openings and cause blockage of shielding gas

44. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Motor driven generators - Transformer rectifiers - and Inverter designs

45. What is the purpose of the shielding gas used in GMAW?
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination

46. Draw a typical volt amp curve for a machine that is designed for GMAW
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow

47. List the three methods of metal transfer with GMAW
3
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
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

48. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
The negative side of a welding unit
The resistace to electrical current flow increases with it. Causing the electrode to heat
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

49. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Short- circuiting transfer - Globular transfer - Spray transfer
Generally not as accurate
Flux cored wires
Wire feed speed - Voltage control

50. What is the key advantage of short circuiting transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input