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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 is a solenoid valve and what actuates it?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

2. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Spatter problems and poor weld appearance

3. What is a typical flow rate of CO2 for short circuit transfer?
V groove or U groove
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
By there current carrying capacity

4. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity
3
DCEP (Direct Current Electrode Positive) Reverse Polarity

5. List the basic equipment requirements for the GMAW process
85%
AWS and CSA
Minimum distortion due to low heat input
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

6. What processes are constant current (CC) power sources designed to be used with?
...
SMAW - GTAW
Wire feed speed
Aluminum wire

7. What effect does increasing and decreasing the inductance have on the weld?
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3

8. What type of power source is commonly used with a voltage sensing wire feeder?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant current (CC)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Penetration and burn - off rate of the electrode

9. What controls amperage when using GMAW?
...
Wire feed speed - Voltage control
Wire feed speed
The negative side of a welding unit

10. What does a flowmeter do and what does it measure?
Short- circuiting transfer - Globular transfer - Spray transfer
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced

11. Why is a line heater required when using GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire
Dry ice can form within the flow control openings and cause blockage of shielding gas

12. In the GMAW process what does amperage control?
Constant voltage (CV)
Wire feed speed - Voltage control
Gas metal arc welding
Penetration and burn - off rate of the electrode

13. A pull type drive system is usually used on what type of material?
85%
Welding process that joins metals by heating them with an electric arc
Aluminum wire
The time rate of response for the current rise and fall

14. What controls the wire speed on a voltage sensing wire feeder?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Shielding the molten weld metal from atmospheric contamination

15. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Shielding the molten weld metal from atmospheric contamination
Generally not as accurate
Motor driven generators - Transformer rectifiers - and Inverter designs

16. Why is globular transfer generally avoided with GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance
DCEP (Direct Current Electrode Positive) Reverse Polarity
...

17. What wire are knurled drive rolls most commonly used on?
The time rate of response for the current rise and fall
AWS and CSA
Flux cored wires
Minimum distortion due to low heat input

18. What does voltage do in an electrical circuit?
5.8 to 12.5 L/min
Flux cored wires
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas

19. What would be an indication that the drive roll pressure is adjusted correctly?
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)

20. What is the recommended electrode stick- out for .035 solid wire?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
If you dont know this check your phone
1/4 inch to 1/2 inch
SMAW - GTAW

21. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Penetration and burn - off rate of the electrode
Motor driven generators - Transformer rectifiers - and Inverter designs
The time rate of response for the current rise and fall

22. What power sources are used with the GMAW Process?
85%
Motor driven generators - Transformer rectifiers - and Inverter designs
3
These terms are quite restrictive and often technically incorrect

23. What does the term GMAW identify?
Gas metal arc welding
Flux cored wires
Cause flaking - which can clog the liner and contact tube
...

24. List the three methods of metal transfer with GMAW
Constant current (CC)
By there current carrying capacity
Guns
Short- circuiting transfer - Globular transfer - Spray transfer

25. What current and polarity is generally used with GMAW?
...
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity
3

26. How are GMAW guns rated?
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association

27. What type of power source is used with a constant speed wire feeder?
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
Minimum distortion due to low heat input
The time rate of response for the current rise and fall
Constant voltage (CV)

28. What is the maximum distance that hard wire can be successfully pushed?
Spatter problems and poor weld appearance
15 feet (4.5 meters)
The negative side of a welding unit
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

29. What is the disadvantage of the gauge preset type of regulator/flowmeter?
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 is the force that overcomes resistance to allow amperage flow
Generally not as accurate

30. What is an advantage of pulsed arc transfer with GMAW?
Guns
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
The resistace to electrical current flow increases with it. Causing the electrode to heat

31. When is the metal transferred with short circuit transfer?
Higher 26 to 35 arc volts
20 to 200 times per second
When the filler wire is in direct contract with the base metal
Controls the rate of flow of a shielding gas to the gun nozzle

32. 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) Reverse Polarity
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

33. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders

34. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
The Arc voltage
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association

35. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
When the filler wire is in direct contract with the base metal
V groove or U groove
If you dont know this check your phone

36. List the factors that determine the mode of metal transfer
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
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

37. In the GMAW process what does voltage control?
Puddle fluidity
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas

38. What does the wire feeder control?
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)

39. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Minutes of elapsed time continually run (out of 10 minutes)
Duty cycle
...
Wire feed speed

40. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Insufficient current to melt the wire off cleanly
Higher 26 to 35 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts

41. What 2 controls are found on a GMAW set- up?
...
If you dont know this check your phone
Wire feed speed
Wire feed speed - Voltage control

42. List 3 forms compressed gases may be supplied for welding
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
AWS and CSA
Aluminum wire

43. List several industries that would use GMAW
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association

44. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Short- circuiting transfer - Globular transfer - Spray transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Cause flaking - which can clog the liner and contact tube
85%

45. Draw a typical volt amp curve for a machine that is designed for GMAW
Aluminum wire
If you dont know this check your phone
Spatter problems and poor weld appearance
Guns

46. What is the preferred drive roll design for solid wires?
Spatter problems and poor weld appearance
V groove or U groove
12 to 22 arc volts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

47. Why is a fiber washer required and what cylinder gas requires it?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Wire feed speed
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)

48. Give a description of 'pinch effect'
Duty cycle
Guns
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

49. List 3 wire drive systems and give a short description of each
Constant current (CC)
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
Speed of the feed motor and - starting / stopping electrode feed
National Electrical Manufactures Association

50. What is the main purpose of 'slope'?
The negative side of a welding unit
Welding process that joins metals by heating them with an electric arc
To limit the short circuiting current so that spatter is reduced
AWS and CSA