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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 type of power source is commonly used with a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
V groove or U groove
Constant current (CC)

2. What is the main purpose of 'slope'?
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced
Constant current (CC)

3. A 10 minute cycle of welding time vs cooling time a given machine can handle.
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle

4. What current and polarity is generally used with GMAW?
Gives arc voltage values to the control system of the feeder
DCEP (Direct Current Electrode Positive) Reverse Polarity
3
To prevent drawing of liquid CO2 (Carbon Dioxide)

5. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)
AWS and CSA

6. Why is globular transfer generally avoided with GMAW?
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Spatter problems and poor weld appearance

7. What is the required arc voltage used for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To limit the short circuiting current so that spatter is reduced
12 to 22 arc volts
Guns

8. List 3 forms compressed gases may be supplied for welding
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

9. List several industries that would use GMAW
Spatter problems and poor weld appearance
Pressure vessels and the piping industry
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

10. What type of power source is used with a constant speed wire feeder?
Insufficient current to melt the wire off cleanly
20 to 200 times per second
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)

11. What processes are constant current (CC) power sources designed to be used with?
...
5.8 to 12.5 L/min
SMAW - GTAW
The negative side of a welding unit

12. What is another term for electrode holders for GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed
Guns
Reducing the gas source pressure to a constant working pressure

13. 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
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
3

14. What would be an indication that the drive roll pressure is adjusted correctly?
Pressure vessels and the piping industry
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle
Insufficient current to melt the wire off cleanly

15. What effect does increasing and decreasing the inductance have on the weld?
To prevent leakage - Carbon Dioxide (CO2)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

16. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input

17. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Penetration and burn - off rate of the electrode
Constant voltage (CV)
Motor driven generators - Transformer rectifiers - and Inverter designs

18. Draw a typical volt amp curve for a machine that is designed for GMAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer

19. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Dry ice can form within the flow control openings and cause blockage of shielding gas
12 to 22 arc volts
If you dont know this check your phone

20. What does inductance control?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The time rate of response for the current rise and fall
Flux cored wires
Spatter problems and poor weld appearance

21. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Guns
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

22. 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
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
12 to 22 arc volts

23. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly
1/4 inch to 1/2 inch

24. What is the recommended electrode stick- out for .035 solid wire?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced

25. What does a flowmeter do and what does it measure?
Speed of the feed motor and - starting / stopping electrode feed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle

26. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Shielding the molten weld metal from atmospheric contamination
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
1/4 inch to 1/2 inch

27. List the factors that determine the mode of metal transfer
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit

28. What power sources are used with the GMAW Process?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed - Voltage control
Flux cored wires

29. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
12 to 22 arc volts
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

30. What does the term GMAW identify?
The Arc voltage
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
DCEP (Direct Current Electrode Positive) Reverse Polarity

31. What 2 organizations designate specifications for GMAW wires?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association
AWS and CSA

32. What is a solenoid valve and what actuates it?
V groove or U groove
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
Speed of the feed motor and - starting / stopping electrode feed

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
12 to 22 arc volts
15 feet (4.5 meters)
Flux cored wires

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

35. Why must CO2 cylinders be used in the vertical position?
National Electrical Manufactures Association
To prevent drawing of liquid CO2 (Carbon Dioxide)
Guns
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

36. List 3 wire drive systems and give a short description of each
Wire feed speed
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
Minutes of elapsed time continually run (out of 10 minutes)
85%

37. A pull type drive system is usually used on what type of material?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire
Spatter problems and poor weld appearance
Minimum distortion due to low heat input

38. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
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
Constant current (CC)
3

39. What controls amperage when using GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
5.8 to 12.5 L/min
Wire feed speed
Higher 26 to 35 arc volts

40. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder

41. What does voltage do in an electrical circuit?
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry
Gas metal arc welding

42. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
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
Cause flaking - which can clog the liner and contact tube

43. What output on the welding machine is used to rate the duty cycle?
Pressure - The rate of flow of a shielding gas
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity

44. What is the maximum distance that hard wire can be successfully pushed?
Spatter problems and poor weld appearance
5.8 to 12.5 L/min
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder

45. What does the abbreviation NEMA stand for?
By there current carrying capacity
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association

46. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts
85%
If you dont know this check your phone

47. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent leakage - Carbon Dioxide (CO2)
Constant- speed wire feeders and Voltage- sennsing wire feeders

48. What wire are knurled drive rolls most commonly used on?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Flux cored wires
The Arc voltage
Insufficient current to melt the wire off cleanly

49. How are GMAW guns rated?
Gas metal arc welding
12 to 22 arc volts
Constant current (CC)
By there current carrying capacity

50. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
...