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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. In the GMAW process what does amperage control?
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination
Cause flaking - which can clog the liner and contact tube

2. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
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Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

3. What does a flowmeter do and what does it measure?
Shielding the molten weld metal from atmospheric contamination
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Controls the rate of flow of a shielding gas to the gun nozzle

4. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
The time rate of response for the current rise and fall
SMAW - GTAW

5. Why is a line heater required when using GMAW?
...
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle

6. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second
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The Arc voltage

7. Draw a typical volt amp curve for a machine that is designed for GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
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(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode

8. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Guns
(DCEP) Direct Current Electrode Positive or Reverse polarity
Short- circuiting transfer - Globular transfer - Spray transfer
To limit the short circuiting current so that spatter is reduced

9. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Minimum distortion due to low heat input

10. What does voltage do in an electrical circuit?
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow

11. Why is a fiber washer required and what cylinder gas requires it?
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. 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
Speed of the feed motor and - starting / stopping electrode feed
Constant current (CC)
3

13. A pull type drive system is usually used on what type of material?
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)

14. What is an advantage of pulsed arc transfer with GMAW?
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
SMAW - GTAW

15. In the GMAW process what does voltage control?
Minimum distortion due to low heat input
Welding process that joins metals by heating them with an electric arc
Puddle fluidity
Cause flaking - which can clog the liner and contact tube

16. What output on the welding machine is used to rate the duty cycle?
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)

17. What type of power source is commonly used with a voltage sensing wire feeder?
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced
85%
Constant current (CC)

18. What is the purpose of the shielding gas used in GMAW?
Aluminum wire
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity

19. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
DCEP (Direct Current Electrode Positive) Reverse Polarity
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination

20. 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)
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas

21. How are GMAW guns rated?
By there current carrying capacity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Puddle fluidity

22. List 3 wire drive systems and give a short description of each
Speed of the feed motor and - starting / stopping electrode feed
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

23. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Higher 26 to 35 arc volts
Gas metal arc welding
Gives arc voltage values to the control system of the feeder
Cause flaking - which can clog the liner and contact tube

24. 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
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity

25. List several industries that would use GMAW
Pressure vessels and the piping industry
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)

26. 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
Constant- speed wire feeders and Voltage- sennsing wire feeders

27. What effect does increasing and decreasing the inductance have on the weld?
Generally not as accurate
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

28. What is a solenoid valve and what actuates it?
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
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

29. What is another term for electrode holders for GMAW?
Minimum distortion due to low heat input
Guns
To prevent leakage - Carbon Dioxide (CO2)
Constant current (CC)

30. List the factors that determine the mode of metal transfer
Puddle fluidity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA
Duty cycle

31. What does the wire feeder control?
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Motor driven generators - Transformer rectifiers - and Inverter designs

32. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant voltage (CV)

33. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry
12 to 22 arc volts
Higher 26 to 35 arc volts

34. List the three methods of metal transfer with GMAW
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer

35. What is the main purpose of 'slope'?
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
Spatter problems and poor weld appearance
To limit the short circuiting current so that spatter is reduced
Constant current (CC)

36. List the basic equipment requirements for the GMAW process
3
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

37. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Duty cycle
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
To prevent drawing of liquid CO2 (Carbon Dioxide)

38. What type of power source is used with a constant speed wire feeder?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)

39. What is the key advantage of short circuiting transfer?
National Electrical Manufactures Association
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
Minimum distortion due to low heat input

40. What power sources are used with the GMAW Process?
Shielding the molten weld metal from atmospheric contamination
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
Wire feed speed

41. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage

42. What 2 controls are found on a GMAW set- up?
Constant voltage (CV)
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feed speed - Voltage control

43. What is the maximum distance that hard wire can be successfully pushed?
Reducing the gas source pressure to a constant working pressure
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)

44. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Controls the rate of flow of a shielding gas to the gun nozzle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
(DCEP) Direct Current Electrode Positive or Reverse polarity

45. What is the preferred drive roll design for solid wires?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
V groove or U groove
Constant current (CC)
Cause flaking - which can clog the liner and contact tube

46. What processes are constant current (CC) power sources designed to be used with?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA
SMAW - GTAW

47. What is the effect of too much slope?
Penetration and burn - off rate of the electrode
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat
Insufficient current to melt the wire off cleanly

48. Why is globular transfer generally avoided with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Spatter problems and poor weld appearance
12 to 22 arc volts
Motor driven generators - Transformer rectifiers - and Inverter designs

49. What is a typical flow rate of CO2 for short circuit transfer?
Generally not as accurate
5.8 to 12.5 L/min
The negative side of a welding unit
Constant voltage (CV)

50. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
AWS and CSA
85%
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW