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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 minimum % value of argon that must be present to use the spray transfer method of GMAW?
AWS and CSA
National Electrical Manufactures Association
Aluminum wire
85%

2. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle

3. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Cause flaking - which can clog the liner and contact tube
Generally not as accurate
If you dont know this check your phone

4. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Reducing the gas source pressure to a constant working pressure
AWS and CSA
...

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
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input

6. What is the purpose of a regulator and what does it indicate on its gauges?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
If you dont know this check your phone

7. Give a description of 'pinch effect'
Wire feed speed - Voltage control
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input

8. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

9. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

10. When is the metal transferred with short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed
When the filler wire is in direct contract with the base metal
15 feet (4.5 meters)

11. What is the purpose of the shielding gas used in GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of 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
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination

12. What does voltage do in an electrical circuit?
Duty cycle
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas

13. What controls the wire speed on a voltage sensing wire feeder?
Wire feed speed - Voltage control
By there current carrying capacity
The Arc voltage
Spatter problems and poor weld appearance

14. What power sources are used with the GMAW Process?
The time rate of response for the current rise and fall
Motor driven generators - Transformer rectifiers - and Inverter designs
SMAW - GTAW
Puddle fluidity

15. Why is a line heater required when using GMAW?
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
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min

16. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
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
The negative side of a welding unit

17. What is an advantage of pulsed arc transfer with GMAW?
Constant current (CC)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

18. What is the required arc voltage used for short circuit transfer?
Duty cycle
85%
By there current carrying capacity
12 to 22 arc volts

19. Why is the term GMAW preferred over MIG or MAG?
Constant current (CC)
Constant voltage (CV)
These terms are quite restrictive and often technically incorrect
...

20. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
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
Gives arc voltage values to the control system of the feeder

21. Draw a typical volt amp curve for a machine that is designed for GMAW
5.8 to 12.5 L/min
When the filler wire is in direct contract with the base metal
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

22. List the three methods of metal transfer with GMAW
3
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer
Constant current (CC)

23. What is another term for electrode holders for GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Guns
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal

24. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect
Flux cored wires

25. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Generally not as accurate
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

26. What wire are knurled drive rolls most commonly used on?
Shielding the molten weld metal from atmospheric contamination
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts
Flux cored wires

27. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Penetration and burn - off rate of the electrode
Spatter problems and poor weld appearance
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

28. List the factors that determine the mode of metal transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Shielding the molten weld metal from atmospheric contamination
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

29. What controls amperage when using GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Guns
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed

30. Why must CO2 cylinders be used in the vertical position?
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)
Minimum distortion due to low heat input

31. What does a flowmeter do and what does it measure?
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat
Controls the rate of flow of a shielding gas to the gun nozzle
V groove or U groove

32. What 2 controls are found on a GMAW set- up?
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
Duty cycle

33. What type of power source is commonly used with a voltage sensing wire feeder?
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
Constant current (CC)
85%
Generally not as accurate

34. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The negative side of a welding unit
Generally not as accurate
The time rate of response for the current rise and fall

35. What is the preferred drive roll design for solid wires?
V groove or U groove
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed

36. What does inductance control?
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)
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

37. List 3 wire drive systems and give a short description of each
Minimum distortion due to low heat input
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
Puddle fluidity
1/4 inch to 1/2 inch

38. What would be an indication that the drive roll pressure is adjusted correctly?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
SMAW - GTAW
These terms are quite restrictive and often technically incorrect

39. What is the effect of too much slope?
Gas metal arc welding
Insufficient current to melt the wire off cleanly
The Arc voltage
If you dont know this check your phone

40. What does the wire feeder control?
Puddle fluidity
Wire feed speed
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect

41. In the GMAW process what does amperage control?
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode
Guns
Insufficient current to melt the wire off cleanly

42. List several industries that would use GMAW
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed
Gas metal arc welding

43. In the GMAW process what does voltage control?
Flux cored wires
Puddle fluidity
Duty cycle
SMAW - GTAW

44. What is the maximum distance that hard wire can be successfully pushed?
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
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

45. Why is globular transfer generally avoided with GMAW?
Duty cycle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Spatter problems and poor weld appearance
Gas metal arc welding

46. Why is a fiber washer required and what cylinder gas requires it?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
These terms are quite restrictive and often technically incorrect

47. What does the abbreviation NEMA stand for?
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
National Electrical Manufactures Association

48. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Spatter problems and poor weld appearance
3
SMAW - GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs

49. A pull type drive system is usually used on what type of material?
Aluminum wire
If you dont know this check your phone
SMAW - GTAW
Duty cycle

50. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)