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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 main purpose of 'slope'?
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination

2. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
If you dont know this check your phone
Wire feed speed
85%
1/4 inch to 1/2 inch

3. List the factors that determine the mode of metal transfer
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
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

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder
Wire feed speed

5. What power sources are used with the GMAW Process?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Insufficient current to melt the wire off cleanly
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate

6. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
Guns
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7. What type of power source is used with a constant speed wire feeder?
Aluminum wire
Constant voltage (CV)
...
Voltage is the force that overcomes resistance to allow amperage flow

8. What wire are knurled drive rolls most commonly used on?
Aluminum wire
The negative side of a welding unit
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer

9. List 3 wire drive systems and give a short description of each
15 feet (4.5 meters)
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
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

10. What does the abbreviation NEMA stand for?
3
Insufficient current to melt the wire off cleanly
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association

11. What is another term for electrode holders for GMAW?
5.8 to 12.5 L/min
Duty cycle
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. What processes are constant current (CC) power sources designed to be used with?
Penetration and burn - off rate of the electrode
SMAW - GTAW
These terms are quite restrictive and often technically incorrect
Voltage is the force that overcomes resistance to allow amperage flow

13. What controls amperage when using GMAW?
Pressure - The rate of flow of a shielding gas
Wire feed speed
Constant- speed wire feeders and Voltage- sennsing wire feeders
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

14. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Spatter problems and poor weld appearance
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)

15. What does a flowmeter do and what does it measure?
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle

16. What is the preferred drive roll design for solid wires?
The time rate of response for the current rise and fall
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
V groove or U groove
To limit the short circuiting current so that spatter is reduced

17. What would be an indication that the drive roll pressure is adjusted correctly?
Gives arc voltage values to the control system of the feeder
Wire feeds smoothly (yet will slip should a problem occur in the gun)
AWS and CSA
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

18. A pull type drive system is usually used on what type of material?
Aluminum wire
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

19. List the basic equipment requirements for the GMAW process
Controls the rate of flow of a shielding gas to the gun nozzle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minutes of elapsed time continually run (out of 10 minutes)
85%

20. In the GMAW process what does voltage control?
Flux cored wires
Puddle fluidity
Gives arc voltage values to the control system of the feeder
12 to 22 arc volts

21. What output on the welding machine is used to rate the duty cycle?
Guns
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
Welding process that joins metals by heating them with an electric arc

22. What is a solenoid valve and what actuates it?
5.8 to 12.5 L/min
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
3
Shielding the molten weld metal from atmospheric contamination

23. Why is the term GMAW preferred over MIG or MAG?
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect

24. What does the term GMAW identify?
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding

25. What current and polarity is generally used with GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity

26. 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
(DCEP) Direct Current Electrode Positive or Reverse polarity
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer

27. What is the key advantage of short circuiting transfer?
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input

28. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control
SMAW - GTAW
Generally not as accurate

29. Regulators control_____________ flowmeters SHOW____________.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
20 to 200 times per second
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

30. List several industries that would use GMAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
Flux cored wires
Pressure vessels and the piping industry
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

31. What 2 organizations designate specifications for GMAW wires?
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
Spatter problems and poor weld appearance
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

32. What is the purpose of the shielding gas used in GMAW?
Generally not as accurate
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)

33. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
Shielding the molten weld metal from atmospheric contamination
Higher 26 to 35 arc volts

34. When is the metal transferred with short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
When the filler wire is in direct contract with the base metal
National Electrical Manufactures Association
85%

35. What is an advantage of pulsed arc transfer with GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
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
85%

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

37. Give a description of 'pinch effect'
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second
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

38. Why must CO2 cylinders be used in the vertical position?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)
The negative side of a welding unit

39. List the three methods of metal transfer with GMAW
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc
12 to 22 arc volts

40. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
(DCEP) Direct Current Electrode Positive or Reverse polarity
Cause flaking - which can clog the liner and contact tube

41. Why is a fiber washer required and what cylinder gas requires it?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect

42. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
1/4 inch to 1/2 inch
Shielding the molten weld metal from atmospheric contamination
...
If you dont know this check your phone

43. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate
Controls the rate of flow of a shielding gas to the gun nozzle
Gives arc voltage values to the control system of the feeder

44. What does inductance control?
The time rate of response for the current rise and fall
12 to 22 arc volts
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas

45. What is the required arc voltage used for short circuit transfer?
Penetration and burn - off rate of the electrode
SMAW - GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts

46. List 3 forms compressed gases may be supplied for welding
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage

47. What controls the wire speed on a voltage sensing wire feeder?
Spatter problems and poor weld appearance
The Arc voltage
National Electrical Manufactures Association
To prevent drawing of liquid CO2 (Carbon Dioxide)

48. What is the recommended electrode stick- out for .035 solid wire?
Cause flaking - which can clog the liner and contact tube
SMAW - GTAW
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch

49. Give a brief description of the GMAW process
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Welding process that joins metals by heating them with an electric arc
3

50. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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