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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. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
5.8 to 12.5 L/min
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube

2. 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
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced

3. What is the purpose of a regulator and what does it indicate on its gauges?
Voltage is the force that overcomes resistance to allow amperage flow
Reducing the gas source pressure to a constant working pressure
1/4 inch to 1/2 inch
National Electrical Manufactures Association

4. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage

5. What effect does increasing and decreasing the inductance have on the weld?
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
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder

6. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
5.8 to 12.5 L/min
15 feet (4.5 meters)
...
Penetration and burn - off rate of the electrode

7. What does voltage do in an electrical circuit?
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity

8. 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
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
15 feet (4.5 meters)
Motor driven generators - Transformer rectifiers - and Inverter designs

9. What does inductance control?
Constant voltage (CV)
National Electrical Manufactures Association
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode

10. What does the wire feeder control?
AWS and CSA
Wire feed speed
Puddle fluidity
Speed of the feed motor and - starting / stopping electrode feed

11. What is another term for electrode holders for GMAW?
Guns
12 to 22 arc volts
When the filler wire is in direct contract with the base metal
The Arc voltage

12. What type of power source is used with a constant speed wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)
V groove or U groove
Short- circuiting transfer - Globular transfer - Spray transfer

13. In the GMAW process what does voltage control?
Cause flaking - which can clog the liner and contact tube
Puddle fluidity
Penetration and burn - off rate of the electrode
Generally not as accurate

14. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
Puddle fluidity
Welding process that joins metals by heating them with an electric arc

15. How are GMAW guns rated?
Wire feed speed - Voltage control
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination

16. Why is a line heater required when using GMAW?
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
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min

17. When is the metal transferred with short circuit transfer?
Welding process that joins metals by heating them with an electric arc
When the filler wire is in direct contract with the base metal
20 to 200 times per second
Wire feed speed

18. What processes are constant current (CC) power sources designed to be used with?
Aluminum wire
The resistace to electrical current flow increases with it. Causing the electrode to heat
V groove or U groove
SMAW - GTAW

19. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Wire feed speed
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity

20. What 2 organizations designate specifications for GMAW wires?
Minimum distortion due to low heat input
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association

21. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)
...
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

22. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Wire feed speed - Voltage control
5.8 to 12.5 L/min
(DCEP) Direct Current Electrode Positive or Reverse polarity
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

23. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
The negative side of a welding unit
Reducing the gas source pressure to a constant working pressure

24. List the factors that determine the mode of metal transfer
Wire feed speed
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

25. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

26. What output on the welding machine is used to rate the duty cycle?
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)
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

27. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Pressure vessels and the piping industry
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch

28. What does a flowmeter do and what does it measure?
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle

29. What wire are knurled drive rolls most commonly used on?
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
Gives arc voltage values to the control system of the feeder
Flux cored wires

30. What does the term GMAW identify?
Gas metal arc welding
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)

31. What is the maximum distance that hard wire can be successfully pushed?
Wire feed speed - Voltage control
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA

32. List 3 forms compressed gases may be supplied for welding
SMAW - GTAW
To prevent leakage - Carbon Dioxide (CO2)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)

33. What controls the wire speed on a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
Constant voltage (CV)
Higher 26 to 35 arc volts

34. List the basic equipment requirements for the GMAW process
15 feet (4.5 meters)
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity

35. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube

36. What controls amperage when using GMAW?
To limit the short circuiting current so that spatter is reduced
Wire feed speed
3
Constant current (CC)

37. What is a typical flow rate of CO2 for short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity
1/4 inch to 1/2 inch

38. A pull type drive system is usually used on what type of material?
5.8 to 12.5 L/min
Aluminum wire
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
If you dont know this check your phone

39. What power sources are used with the GMAW Process?
...
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas

40. What is the required arc voltage used for short circuit transfer?
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
12 to 22 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle

41. How many times per second does short circuiting take place?
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
...
20 to 200 times per second

42. What is the preferred drive roll design for solid wires?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
Reducing the gas source pressure to a constant working pressure
V groove or U groove

43. In the GMAW process what does amperage control?
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode
Aluminum wire

44. What current and polarity is generally used with GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Duty cycle
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

45. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Gives arc voltage values to the control system of the feeder
85%
Motor driven generators - Transformer rectifiers - and Inverter designs

46. What is the main purpose of 'slope'?
SMAW - GTAW
3
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced

47. List several industries that would use GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
Reducing the gas source pressure to a constant working pressure
Pressure vessels and the piping industry

48. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The resistace to electrical current flow increases with it. Causing the electrode to heat
1/4 inch to 1/2 inch
85%

49. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc
Minimum distortion due to low heat input

50. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gives arc voltage values to the control system of the feeder
Higher 26 to 35 arc volts
Gas metal arc welding