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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 is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant voltage (CV)
If you dont know this check your phone

2. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Puddle fluidity
National Electrical Manufactures Association
12 to 22 arc volts

3. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
3
Puddle fluidity
85%

4. What type of power source is used with a constant speed wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant voltage (CV)
1/4 inch to 1/2 inch

5. What is the maximum distance that hard wire can be successfully pushed?
Higher 26 to 35 arc volts
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Minimum distortion due to low heat input

6. What is a solenoid valve and what actuates it?
Welding process that joins metals by heating them with an electric arc
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure

7. What output on the welding machine is used to rate the duty cycle?
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)

8. A pull type drive system is usually used on what type of material?
Guns
Insufficient current to melt the wire off cleanly
Aluminum wire
Wire feed speed - Voltage control

9. What is a typical flow rate of CO2 for short circuit transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)

10. What 2 organizations designate specifications for GMAW wires?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
AWS and CSA
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding process that joins metals by heating them with an electric arc

11. What power sources are used with the GMAW Process?
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
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs

12. Why is globular transfer generally avoided with GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
Speed of the feed motor and - starting / stopping electrode feed

13. List the basic equipment requirements for the GMAW process
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow

14. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The Arc voltage
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
Gas metal arc welding

15. Give a description of 'pinch effect'
Gas metal arc welding
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns
SMAW - GTAW

16. What does the wire feeder control?
When the filler wire is in direct contract with the base metal
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
...

17. What wire are knurled drive rolls most commonly used on?
Flux cored wires
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
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity

18. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Penetration and burn - off rate of the electrode
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

19. In the GMAW process what does voltage control?
Penetration and burn - off rate of the electrode
Puddle fluidity
If you dont know this check your phone
Generally not as accurate

20. List the three methods of metal transfer with GMAW
Motor driven generators - Transformer rectifiers - and Inverter designs
The resistace to electrical current flow increases with it. Causing the electrode to heat
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer

21. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant voltage (CV)
If you dont know this check your phone
National Electrical Manufactures Association
Pressure - The rate of flow of a shielding gas

22. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
...
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

23. What happens when the electrode extension is increased?
12 to 22 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Flux cored wires
(DCEP) Direct Current Electrode Positive or Reverse polarity

24. Why is a fiber washer required and what cylinder gas requires it?
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

25. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
15 feet (4.5 meters)
Higher 26 to 35 arc volts
Wire feed speed

26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
When the filler wire is in direct contract with the base metal
Duty cycle
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry

27. What is an advantage of pulsed arc transfer with GMAW?
If you dont know this check your phone
85%
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns

28. List 3 wire drive systems and give a short description of each
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
1/4 inch to 1/2 inch
Minutes of elapsed time continually run (out of 10 minutes)

29. How are GMAW guns rated?
By there current carrying capacity
Short- circuiting transfer - Globular transfer - Spray transfer
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
15 feet (4.5 meters)

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate
Constant voltage (CV)
If you dont know this check your phone

31. List the factors that determine the mode of metal transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly
The Arc voltage
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

32. What is the key advantage of short circuiting transfer?
Pressure - The rate of flow of a shielding gas
National Electrical Manufactures Association
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)

33. What controls amperage when using GMAW?
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed
Speed of the feed motor and - starting / stopping electrode feed

34. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone

35. What type of power source is commonly used with a voltage sensing wire feeder?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity
Constant current (CC)

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage
15 feet (4.5 meters)

37. Why is the term GMAW preferred over MIG or MAG?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
These terms are quite restrictive and often technically incorrect

38. List 3 forms compressed gases may be supplied for welding
To prevent leakage - Carbon Dioxide (CO2)
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone

39. What is another term for electrode holders for GMAW?
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure
Guns

40. Why must CO2 cylinders be used in the vertical position?
Wire feed speed - Voltage control
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)
To limit the short circuiting current so that spatter is reduced

41. List several industries that would use GMAW
Pressure vessels and the piping industry
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns

42. What is the purpose of the shielding gas used in GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Shielding the molten weld metal from atmospheric contamination
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc

43. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Pressure vessels and the piping industry
The time rate of response for the current rise and fall
Aluminum wire

44. How many times per second does short circuiting take place?
Constant current (CC)
20 to 200 times per second
Aluminum wire
Cause flaking - which can clog the liner and contact tube

45. What does a flowmeter do and what does it measure?
85%
Controls the rate of flow of a shielding gas to the gun nozzle
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

46. What is the required arc voltage used for short circuit transfer?
If you dont know this check your phone
12 to 22 arc volts
Constant voltage (CV)
20 to 200 times per second

47. What is the recommended electrode stick- out for .035 solid wire?
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
Minimum distortion due to low heat input

48. What does inductance control?
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)

49. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
Generally not as accurate

50. 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
Duty cycle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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