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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. Why is a fiber washer required and what cylinder gas requires it?
When the filler wire is in direct contract with the base metal
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)
Generally not as accurate

2. What controls the wire speed on a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage
AWS and CSA

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Wire feed speed

4. List the factors that determine the mode of metal transfer
Constant voltage (CV)
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
Pressure - The rate of flow of a shielding gas

5. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity
3

6. What is the recommended electrode stick- out for .035 solid wire?
Duty cycle
1/4 inch to 1/2 inch
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire

7. What is another term for electrode holders for GMAW?
V groove or U groove
Speed of the feed motor and - starting / stopping electrode feed
...
Guns

8. What happens when the electrode extension is increased?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure

9. A pull type drive system is usually used on what type of material?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Aluminum wire
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

10. What does a flowmeter do and what does it measure?
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

11. What is the main purpose of 'slope'?
The time rate of response for the current rise and fall
Puddle fluidity
By there current carrying capacity
To limit the short circuiting current so that spatter is reduced

12. Draw a typical volt amp curve for a machine that is designed for GMAW
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Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect

13. What is a typical flow rate of CO2 for short circuit transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

14. Regulators control_____________ flowmeters SHOW____________.
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity

15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch
Shielding the molten weld metal from atmospheric contamination

16. What does the wire feeder control?
Gas metal arc welding
Higher 26 to 35 arc volts
Speed of the feed motor and - starting / stopping electrode feed
National Electrical Manufactures Association

17. What is the preferred drive roll design for solid wires?
5.8 to 12.5 L/min
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure
V groove or U groove

18. What is the maximum distance that hard wire can be successfully pushed?
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs
Spatter problems and poor weld appearance
15 feet (4.5 meters)

19. When is the metal transferred with short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...
When the filler wire is in direct contract with the base metal

20. Why is a line heater required when using GMAW?
Puddle fluidity
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts

21. List 3 forms compressed gases may be supplied for welding
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

22. Why is the term GMAW preferred over MIG or MAG?
To prevent leakage - Carbon Dioxide (CO2)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect

23. List 3 wire drive systems and give a short description of each
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
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
Higher 26 to 35 arc volts

24. What type of power source is used with a constant speed wire feeder?
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)

25. What does the term GMAW identify?
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gas metal arc welding

26. What would be an indication that the drive roll pressure is adjusted correctly?
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85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The resistace to electrical current flow increases with it. Causing the electrode to heat

27. What is the purpose of a regulator and what does it indicate on its gauges?
The time rate of response for the current rise and fall
Gas metal arc welding
Cause flaking - which can clog the liner and contact tube
Reducing the gas source pressure to a constant working pressure

28. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
1/4 inch to 1/2 inch
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input

29. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Guns
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders

30. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%
By there current carrying capacity
Pressure - The rate of flow of a shielding gas

31. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Minutes of elapsed time continually run (out of 10 minutes)
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders

32. What is the disadvantage of the gauge preset type of regulator/flowmeter?
15 feet (4.5 meters)
Duty cycle
Generally not as accurate
20 to 200 times per second

33. How many times per second does short circuiting take place?
12 to 22 arc volts
20 to 200 times per second
Flux cored wires
If you dont know this check your phone

34. What are the 2 types of wire feeders available?
National Electrical Manufactures Association
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders
AWS and CSA

35. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
Motor driven generators - Transformer rectifiers - and Inverter designs

36. List the three methods of metal transfer with GMAW
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer
...
12 to 22 arc volts

37. List the basic equipment requirements for the GMAW process
The Arc voltage
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gas metal arc welding

38. A 10 minute cycle of welding time vs cooling time a given machine can handle.
20 to 200 times per second
1/4 inch to 1/2 inch
Duty cycle
15 feet (4.5 meters)

39. What does the abbreviation NEMA stand for?
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association
20 to 200 times per second
Gives arc voltage values to the control system of the feeder

40. Give a brief description of the GMAW process
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed

41. What does inductance control?
The time rate of response for the current rise and fall
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association
If you dont know this check your phone

42. What 2 controls are found on a GMAW set- up?
85%
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...

43. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Insufficient current to melt the wire off cleanly
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
Aluminum wire

45. What controls amperage when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
Wire feed speed
If you dont know this check your phone

46. What processes are constant current (CC) power sources designed to be used with?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
Higher 26 to 35 arc volts

47. Why is globular transfer generally avoided with GMAW?
5.8 to 12.5 L/min
Spatter problems and poor weld appearance
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

48. What does voltage do in an electrical circuit?
15 feet (4.5 meters)
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

49. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer
...

50. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
SMAW - GTAW
When the filler wire is in direct contract with the base metal
15 feet (4.5 meters)