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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 effect does increasing and decreasing the inductance have on the weld?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The time rate of response for the current rise and fall
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant current (CC)

2. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed

3. How are GMAW guns rated?
1/4 inch to 1/2 inch
20 to 200 times per second
By there current carrying capacity
Gives arc voltage values to the control system of the feeder

4. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
15 feet (4.5 meters)
SMAW - GTAW

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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...
Spatter problems and poor weld appearance
SMAW - GTAW

6. What does inductance control?
Wire feed speed
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
The time rate of response for the current rise and fall

7. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
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Spatter problems and poor weld appearance
Constant voltage (CV)

8. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
These terms are quite restrictive and often technically incorrect
Duty cycle

9. 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)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
85%

10. What does the term GMAW identify?
Pressure vessels and the piping industry
AWS and CSA
Gas metal arc welding
Dry ice can form within the flow control openings and cause blockage of shielding gas

11. What is the main purpose of 'slope'?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
15 feet (4.5 meters)

12. What is the purpose of a regulator and what does it indicate on its gauges?
5.8 to 12.5 L/min
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. What controls amperage when using GMAW?
AWS and CSA
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed

14. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Cause flaking - which can clog the liner and contact tube
1/4 inch to 1/2 inch
Generally not as accurate
National Electrical Manufactures Association

15. What does voltage do in an electrical circuit?
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Short- circuiting transfer - Globular transfer - Spray transfer
Voltage is the force that overcomes resistance to allow amperage flow

16. Why is the term GMAW preferred over MIG or MAG?
Aluminum wire
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

17. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Aluminum wire
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas

18. What does the abbreviation NEMA stand for?
The Arc voltage
20 to 200 times per second
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association

19. 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
...
AWS and CSA
5.8 to 12.5 L/min

20. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Wire feed speed - Voltage control
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination

21. What happens when the electrode extension is increased?
1/4 inch to 1/2 inch
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant current (CC)
AWS and CSA

22. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

23. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced

24. What controls the wire speed on a voltage sensing wire feeder?
15 feet (4.5 meters)
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

25. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
15 feet (4.5 meters)
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%

26. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Minimum distortion due to low heat input
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

27. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle
3
Minimum distortion due to low heat input

28. What is the recommended electrode stick- out for .035 solid wire?
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

29. In the GMAW process what does amperage control?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode

30. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
The time rate of response for the current rise and fall
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

31. What power sources are used with the GMAW Process?
...
Motor driven generators - Transformer rectifiers - and Inverter designs
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

32. Why is a fiber washer required and what cylinder gas requires it?
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)

33. What is the key advantage of short circuiting transfer?
The Arc voltage
The negative side of a welding unit
Minimum distortion due to low heat input
85%

34. What is a typical flow rate of CO2 for short circuit transfer?
...
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
5.8 to 12.5 L/min

35. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Guns
If you dont know this check your phone
The resistace to electrical current flow increases with it. Causing the electrode to heat

36. Regulators control_____________ flowmeters SHOW____________.
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure - The rate of flow of a shielding gas
The Arc voltage

37. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)

38. What is a solenoid valve and what actuates it?
When the filler wire is in direct contract with the base metal
20 to 200 times per second
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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

39. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

40. What is the required arc voltage used for short circuit transfer?
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts

41. What is the maximum distance that hard wire can be successfully pushed?
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
85%
15 feet (4.5 meters)

42. A pull type drive system is usually used on what type of material?
National Electrical Manufactures Association
Aluminum wire
Higher 26 to 35 arc volts
The Arc voltage

43. Why must CO2 cylinders be used in the vertical position?
Generally not as accurate
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
5.8 to 12.5 L/min

44. Why is a line heater required when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The resistace to electrical current flow increases with it. Causing the electrode to heat
Dry ice can form within the flow control openings and cause blockage of shielding gas

45. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Minimum distortion due to low heat input
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube
Duty cycle

46. Give a brief description of the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Welding process that joins metals by heating them with an electric arc
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

47. In the GMAW process what does voltage control?
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
Puddle fluidity

48. 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
If you dont know this check your phone
20 to 200 times per second
Higher 26 to 35 arc volts

49. What does a flowmeter do and what does it measure?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
20 to 200 times per second
Controls the rate of flow of a shielding gas to the gun nozzle
Flux cored wires

50. What is another term for electrode holders for GMAW?
AWS and CSA
20 to 200 times per second
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns