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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. List 3 wire drive systems and give a short description of each
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
Penetration and burn - off rate of the electrode
Cause flaking - which can clog the liner and contact tube

2. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
If you dont know this check your phone

3. What is the main purpose of 'slope'?
5.8 to 12.5 L/min
3
To limit the short circuiting current so that spatter is reduced
...

4. In the GMAW process what does amperage control?
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder
V groove or U groove
Penetration and burn - off rate of the electrode

5. What type of power source is commonly used with a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
Constant current (CC)
When the filler wire is in direct contract with the base metal

6. What is the maximum distance that hard wire can be successfully pushed?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The Arc voltage
(DCEP) Direct Current Electrode Positive or Reverse polarity
15 feet (4.5 meters)

7. Regulators control_____________ flowmeters SHOW____________.
Motor driven generators - Transformer rectifiers - and Inverter designs
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
Pressure - The rate of flow of a shielding gas

8. 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- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant current (CC)

9. Why is globular transfer generally avoided with GMAW?
Constant voltage (CV)
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)

10. What does inductance control?
The time rate of response for the current rise and fall
Generally not as accurate
Aluminum wire
Pressure vessels and the piping industry

11. Give a brief description of the GMAW process
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
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
By there current carrying capacity

12. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
Generally not as accurate
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)

13. What does a flowmeter do and what does it measure?
Reducing the gas source pressure to a constant working pressure
V groove or U groove
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer

14. When is the metal transferred with short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
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. What is the recommended electrode stick- out for .035 solid wire?
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch
V groove or U groove
Welding process that joins metals by heating them with an electric arc

16. Give a description of 'pinch effect'
15 feet (4.5 meters)
DCEP (Direct Current Electrode Positive) Reverse Polarity
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

17. How many times per second does short circuiting take place?
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
20 to 200 times per second
Spatter problems and poor weld appearance
Gas metal arc welding

18. What is another term for electrode holders for GMAW?
Guns
Penetration and burn - off rate of the electrode
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone

19. What type of power source is used with a constant speed wire feeder?
V groove or U groove
Constant voltage (CV)
The negative side of a welding unit
Minimum distortion due to low heat input

20. What controls amperage when using GMAW?
Wire feed speed
When the filler wire is in direct contract with the base metal
1/4 inch to 1/2 inch
...

21. What is the purpose of the shielding gas used in GMAW?
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode

22. List several industries that would use GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc
Wire feed speed
Pressure vessels and the piping industry

23. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minutes of elapsed time continually run (out of 10 minutes)

24. List 3 forms compressed gases may be supplied for welding
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

25. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feed speed
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube

26. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min

27. A pull type drive system is usually used on what type of material?
Flux cored wires
Higher 26 to 35 arc volts
Aluminum wire
20 to 200 times per second

28. What are the 2 types of wire feeders available?
The negative side of a welding unit
Wire feed speed - Voltage control
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders

29. In the GMAW process what does voltage control?
Constant current (CC)
Gives arc voltage values to the control system of the feeder
Puddle fluidity
Gas metal arc welding

30. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Shielding the molten weld metal from atmospheric contamination
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Minimum distortion due to low heat input

31. What wire are knurled drive rolls most commonly used on?
Shielding the molten weld metal from atmospheric contamination
Flux cored wires
3
...

32. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The time rate of response for the current rise and fall
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
Gas metal arc welding

33. What would be an indication that the drive roll pressure is adjusted correctly?
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
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

34. What does the wire feeder control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Guns

35. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Generally not as accurate
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination

37. What is the required arc voltage used for short circuit transfer?
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
V groove or U groove
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

38. What controls the wire speed on a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
The Arc voltage
Constant voltage (CV)
The negative side of a welding unit

39. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
V groove or U groove
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder

40. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Motor driven generators - Transformer rectifiers - and Inverter designs
...

41. List the basic equipment requirements for the GMAW process
Aluminum wire
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
If you dont know this check your phone

42. What does the term GMAW identify?
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
Gas metal arc welding
Penetration and burn - off rate of the electrode

43. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
15 feet (4.5 meters)
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

44. Draw a typical volt amp curve for a machine that is designed for GMAW
Gives arc voltage values to the control system of the feeder
SMAW - GTAW
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders

45. Why is a fiber washer required and what cylinder gas requires it?
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)

46. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder

47. What is the effect of too much slope?
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Insufficient current to melt the wire off cleanly
Reducing the gas source pressure to a constant working pressure

48. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance

49. What happens when the electrode extension is increased?
The negative side of a welding unit
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second

50. What does the abbreviation NEMA stand for?
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association
Speed of the feed motor and - starting / stopping electrode feed