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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. List the basic equipment requirements for the GMAW process
The Arc voltage
Shielding the molten weld metal from atmospheric contamination
Generally not as accurate
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

2. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
National Electrical Manufactures Association
...
Gives arc voltage values to the control system of the feeder
Short- circuiting transfer - Globular transfer - Spray transfer

3. With straight polarity where is 2/3 of the arc energy?
Flux cored wires
Gives arc voltage values to the control system of the feeder
V groove or U groove
The negative side of a welding unit

4. What is the key advantage of short circuiting transfer?
Penetration and burn - off rate of the electrode
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)
(DCEP) Direct Current Electrode Positive or Reverse polarity

5. What output on the welding machine is used to rate the duty cycle?
Insufficient current to melt the wire off cleanly
The negative side of a welding unit
3
Minutes of elapsed time continually run (out of 10 minutes)

6. What type of power source is commonly used with a voltage sensing wire feeder?
...
Higher 26 to 35 arc volts
Constant current (CC)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

7. A pull type drive system is usually used on what type of material?
To limit the short circuiting current so that spatter is reduced
Aluminum wire
Duty cycle
5.8 to 12.5 L/min

8. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
When the filler wire is in direct contract with the base metal

9. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Generally not as accurate

10. What is another term for electrode holders for GMAW?
Guns
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
Minutes of elapsed time continually run (out of 10 minutes)

11. How are GMAW guns rated?
Constant- speed wire feeders and Voltage- sennsing wire feeders
By there current carrying capacity
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle

12. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
DCEP (Direct Current Electrode Positive) Reverse Polarity
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
3

13. In the GMAW process what does amperage control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
The time rate of response for the current rise and fall

14. 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 leakage - Carbon Dioxide (CO2)
3
Guns

15. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Duty cycle

16. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect

17. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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
The time rate of response for the current rise and fall

18. What is the effect of too much slope?
5.8 to 12.5 L/min
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
Puddle fluidity

19. What does the wire feeder control?
5.8 to 12.5 L/min
Flux cored wires
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate

20. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
15 feet (4.5 meters)
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc

21. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
By there current carrying capacity
85%
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)

22. Give a brief description of the GMAW process
...
Puddle fluidity
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

23. 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
Insufficient current to melt the wire off cleanly
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent leakage - Carbon Dioxide (CO2)

24. List 3 forms compressed gases may be supplied for welding
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)

25. In the GMAW process what does voltage control?
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
V groove or U groove
Minimum distortion due to low heat input

26. List the factors that determine the mode of metal transfer
The time rate of response for the current rise and fall
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

27. What is the maximum distance that hard wire can be successfully pushed?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)
V groove or U groove
...

28. What power sources are used with the GMAW Process?
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Reducing the gas source pressure to a constant working pressure
If you dont know this check your phone

29. What effect does increasing and decreasing the inductance have on the weld?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed
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

30. What is a typical flow rate of CO2 for short circuit transfer?
Minimum distortion due to low heat input
Duty cycle
20 to 200 times per second
5.8 to 12.5 L/min

31. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts

32. Draw a typical volt amp curve for a machine that is designed for GMAW
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
Gas metal arc welding

33. List several industries that would use GMAW
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
DCEP (Direct Current Electrode Positive) Reverse Polarity

34. What would be an indication that the drive roll pressure is adjusted correctly?
The time rate of response for the current rise and fall
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Voltage is the force that overcomes resistance to allow amperage flow
DCEP (Direct Current Electrode Positive) Reverse Polarity

35. Why must CO2 cylinders be used in the vertical position?
Gives arc voltage values to the control system of the feeder
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle

36. What current and polarity is generally used with GMAW?
Generally not as accurate
The Arc voltage
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity

37. What is the purpose of the pick- up lead on 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
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure
Gives arc voltage values to the control system of the feeder

38. What is the main purpose of 'slope'?
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
Welding process that joins metals by heating them with an electric arc

39. What happens when the electrode extension is increased?
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat
The time rate of response for the current rise and fall
V groove or U groove

40. Why is a fiber washer required and what cylinder gas requires it?
Shielding the molten weld metal from atmospheric contamination
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)

41. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
To limit the short circuiting current so that spatter is reduced
...

42. What controls amperage when using GMAW?
Aluminum wire
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed

43. What does inductance control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode

44. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
To prevent leakage - Carbon Dioxide (CO2)
Constant current (CC)
National Electrical Manufactures Association

45. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube

46. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed
These terms are quite restrictive and often technically incorrect

47. What is an advantage of pulsed arc transfer with GMAW?
AWS and CSA
If you dont know this check your phone
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

48. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity
Higher 26 to 35 arc volts
12 to 22 arc volts

49. What is the purpose of the shielding gas used in GMAW?
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly

50. What does a flowmeter do and what does it measure?
Welding process that joins metals by heating them with an electric arc
Insufficient current to melt the wire off cleanly
Flux cored wires
Controls the rate of flow of a shielding gas to the gun nozzle