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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. Draw a typical volt amp curve for a machine that is designed for GMAW
The Arc voltage
The time rate of response for the current rise and fall
If you dont know this check your phone
Wire feed speed

2. How many times per second does short circuiting take place?
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal
Dry ice can form within the flow control openings and cause blockage of shielding gas
20 to 200 times per second

3. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Pressure - The rate of flow of a shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs

4. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly

5. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Welding process that joins metals by heating them with an electric arc
Pressure - The rate of flow of a shielding gas
5.8 to 12.5 L/min

6. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect

7. Why is the term GMAW preferred over MIG or MAG?
Guns
V groove or U groove
These terms are quite restrictive and often technically incorrect
The time rate of response for the current rise and fall

8. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall
12 to 22 arc volts
5.8 to 12.5 L/min

9. What is the maximum distance that hard wire can be successfully pushed?
Duty cycle
Cause flaking - which can clog the liner and contact tube
Constant current (CC)
15 feet (4.5 meters)

10. What is an advantage of pulsed arc transfer with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
...

11. When is the metal transferred with short circuit transfer?
Gas metal arc welding
When the filler wire is in direct contract with the base metal
Cause flaking - which can clog the liner and contact tube
Welding process that joins metals by heating them with an electric arc

12. What 2 organizations designate specifications for GMAW wires?
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
V groove or U groove
20 to 200 times per second

13. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Gas metal arc welding
Aluminum wire
Wire feed speed
85%

14. What happens when the electrode extension is increased?
5.8 to 12.5 L/min
Higher 26 to 35 arc volts
To prevent leakage - Carbon Dioxide (CO2)
The resistace to electrical current flow increases with it. Causing the electrode to heat

15. What does a flowmeter do and what does it measure?
Duty cycle
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Constant current (CC)

16. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
By there current carrying capacity
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts

17. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
Constant current (CC)
AWS and CSA
Pressure - The rate of flow of a shielding gas

18. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Duty cycle
Welding process that joins metals by heating them with an electric arc
Spatter problems and poor weld appearance

19. What is another term for electrode holders for GMAW?
If you dont know this check your phone
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns
To limit the short circuiting current so that spatter is reduced

20. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
The time rate of response for the current rise and fall

21. Why is a fiber washer required and what cylinder gas requires it?
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min
SMAW - GTAW

22. List the three methods of metal transfer with GMAW
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
12 to 22 arc volts

23. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

24. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Higher 26 to 35 arc volts
Wire feed speed
Generally not as accurate
Dry ice can form within the flow control openings and cause blockage of shielding gas

25. What does voltage do in an electrical circuit?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle

26. What are the 2 types of wire feeders available?
Minutes of elapsed time continually run (out of 10 minutes)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire
National Electrical Manufactures Association

27. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
To limit the short circuiting current so that spatter is reduced
...
Guns
When the filler wire is in direct contract with the base metal

28. Why is globular transfer generally avoided with GMAW?
Constant current (CC)
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube
Spatter problems and poor weld appearance

29. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts

30. With straight polarity where is 2/3 of the arc energy?
Puddle fluidity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit

31. In the GMAW process what does voltage control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Puddle fluidity
Gives arc voltage values to the control system of the feeder
Gas metal arc welding

32. What type of power source is used with a constant speed wire feeder?
Reducing the gas source pressure to a constant working pressure
12 to 22 arc volts
Constant voltage (CV)
By there current carrying capacity

33. What does inductance control?
The time rate of response for the current rise and fall
SMAW - GTAW
Flux cored wires
Speed of the feed motor and - starting / stopping electrode feed

34. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Gas metal arc welding
Higher 26 to 35 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
20 to 200 times per second

35. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)

36. Why must CO2 cylinders be used in the vertical position?
12 to 22 arc volts
20 to 200 times per second
Constant current (CC)
To prevent drawing of liquid CO2 (Carbon Dioxide)

37. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

38. What is the required arc voltage used for short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minimum distortion due to low heat input
If you dont know this check your phone
12 to 22 arc volts

39. What is a solenoid valve and what actuates it?
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle
Higher 26 to 35 arc volts

40. 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
Generally not as accurate
15 feet (4.5 meters)
...

41. A pull type drive system is usually used on what type of material?
Aluminum wire
Flux cored wires
To limit the short circuiting current so that spatter is reduced
Wire feed speed

42. List 3 forms compressed gases may be supplied for welding
1/4 inch to 1/2 inch
Flux cored wires
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

43. 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
Pressure - The rate of flow of a shielding gas
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

45. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)

46. 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
Duty cycle
Constant current (CC)
Reducing the gas source pressure to a constant working pressure

47. What is the key advantage of short circuiting transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Aluminum wire
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas

48. What is the main purpose of 'slope'?
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
The resistace to electrical current flow increases with it. Causing the electrode to heat

49. What is a typical flow rate of CO2 for short circuit transfer?
Wire feed speed
National Electrical Manufactures Association
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min

50. A 10 minute cycle of welding time vs cooling time a given machine can handle.
85%
Duty cycle
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal