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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 the pick- up lead on a voltage sensing wire feeder?
85%
12 to 22 arc volts
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder

2. Draw a typical volt amp curve for a machine that is designed for GMAW
Motor driven generators - Transformer rectifiers - and Inverter designs
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone
Aluminum wire

3. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Shielding the molten weld metal from atmospheric contamination
3
When the filler wire is in direct contract with the base metal
Speed of the feed motor and - starting / stopping electrode feed

4. List the three methods of metal transfer with GMAW
To limit the short circuiting current so that spatter is reduced
Generally not as accurate
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer

5. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed
National Electrical Manufactures Association
Spatter problems and poor weld appearance

6. What does voltage do in an electrical circuit?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow

7. What is another term for electrode holders for GMAW?
SMAW - GTAW
85%
Guns
Generally not as accurate

8. What is the preferred drive roll design for solid wires?
Pressure vessels and the piping industry
V groove or U groove
Gas metal arc welding
Flux cored wires

9. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Wire feed speed
The negative side of a welding unit
3

10. What current and polarity is generally used with GMAW?
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA
Wire feed speed - Voltage control

11. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
SMAW - GTAW
Wire feed speed
If you dont know this check your phone

12. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gives arc voltage values to the control system of the feeder
85%
15 feet (4.5 meters)

13. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
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

14. What type of power source is commonly used with a voltage sensing wire feeder?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Shielding the molten weld metal from atmospheric contamination
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant current (CC)

15. Why is the term GMAW preferred over MIG or MAG?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Short- circuiting transfer - Globular transfer - Spray transfer
AWS and CSA
These terms are quite restrictive and often technically incorrect

16. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
AWS and CSA
The time rate of response for the current rise and fall
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

17. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min

18. What controls amperage when using GMAW?
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
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed
By there current carrying capacity

19. What does the abbreviation NEMA stand for?
Pressure - The rate of flow of a shielding gas
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association
Constant voltage (CV)

20. What is an advantage of pulsed arc transfer with GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry
Higher 26 to 35 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

21. What output on the welding machine is used to rate the duty cycle?
1/4 inch to 1/2 inch
...
Minutes of elapsed time continually run (out of 10 minutes)
The Arc voltage

22. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gives arc voltage values to the control system of the feeder

23. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Spatter problems and poor weld appearance
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)

24. With straight polarity where is 2/3 of the arc energy?
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The negative side of a welding unit
When the filler wire is in direct contract with the base metal

25. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
V groove or U groove
Pressure vessels and the piping industry
The time rate of response for the current rise and fall
(DCEP) Direct Current Electrode Positive or Reverse polarity

26. What does a flowmeter do and what does it measure?
Constant current (CC)
Gas metal arc welding
Voltage is the force that overcomes resistance to allow amperage flow
Controls the rate of flow of a shielding gas to the gun nozzle

27. 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
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

28. What does the term GMAW identify?
Gives arc voltage values to the control system of the feeder
Gas metal arc welding
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

29. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal
Cause flaking - which can clog the liner and contact tube

30. What processes are constant current (CC) power sources designed to be used with?
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

31. What does inductance control?
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts

32. A pull type drive system is usually used on what type of material?
Aluminum wire
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Flux cored wires
Constant current (CC)
National Electrical Manufactures Association

34. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc

35. Give a description of 'pinch effect'
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Higher 26 to 35 arc volts
Minimum distortion due to low heat input
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

36. A 10 minute cycle of welding time vs cooling time a given machine can handle.
The negative side of a welding unit
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity
Duty cycle

37. In the GMAW process what does voltage control?
12 to 22 arc volts
Gas metal arc welding
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity

38. List several industries that would use GMAW
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry

39. List the basic equipment requirements for the GMAW process
Flux cored wires
By there current carrying capacity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

40. What happens when the electrode extension is increased?
Controls the rate of flow of a shielding gas to the gun nozzle
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns
SMAW - GTAW

41. What is the main purpose of 'slope'?
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
(DCEP) Direct Current Electrode Positive or Reverse polarity
Reducing the gas source pressure to a constant working pressure

42. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
12 to 22 arc volts
If you dont know this check your phone
Wire feed speed
...

43. 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
V groove or U groove
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
Guns

44. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Cause flaking - which can clog the liner and contact tube
Higher 26 to 35 arc volts
12 to 22 arc volts

45. Why is a fiber washer required and what cylinder gas requires it?
Spatter problems and poor weld appearance
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal
...

46. Why must CO2 cylinders be used in the vertical position?
Motor driven generators - Transformer rectifiers - and Inverter designs
Reducing the gas source pressure to a constant working pressure
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)

47. What does the wire feeder control?
Pressure vessels and the piping industry
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed
V groove or U groove

48. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance

49. What 2 organizations designate specifications for GMAW wires?
Welding process that joins metals by heating them with an electric arc
Wire feed speed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
AWS and CSA

50. When is the metal transferred with short circuit transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
Controls the rate of flow of a shielding gas to the gun nozzle
When the filler wire is in direct contract with the base metal