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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. With straight polarity where is 2/3 of the arc energy?
To limit the short circuiting current so that spatter is reduced
Pressure vessels and the piping industry
1/4 inch to 1/2 inch
The negative side of a welding unit

2. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs

3. What output on the welding machine is used to rate the duty cycle?
Cause flaking - which can clog the liner and contact tube
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone

4. What is the maximum distance that hard wire can be successfully pushed?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle
15 feet (4.5 meters)
Constant voltage (CV)

5. What type of power source is commonly used with a voltage sensing wire feeder?
Puddle fluidity
V groove or U groove
Constant current (CC)
Insufficient current to melt the wire off cleanly

6. Why is a line heater required when using GMAW?
Welding process that joins metals by heating them with an electric arc
Dry ice can form within the flow control openings and cause blockage of shielding gas
By there current carrying capacity
Pressure - The rate of flow of a shielding gas

7. What is the main purpose of 'slope'?
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

8. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode
Aluminum wire

9. What 2 organizations designate specifications for GMAW wires?
5.8 to 12.5 L/min
AWS and CSA
3
Flux cored wires

10. What is another term for electrode holders for GMAW?
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

11. List several industries that would use GMAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Guns
Pressure vessels and the piping industry
Higher 26 to 35 arc volts

12. What is the purpose of a regulator and what does it indicate on its gauges?
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
Reducing the gas source pressure to a constant working pressure
If you dont know this check your phone

13. What is the key advantage of short circuiting transfer?
Gas metal arc welding
Flux cored wires
Wire feed speed
Minimum distortion due to low heat input

14. In the GMAW process what does voltage control?
Puddle fluidity
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
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

15. List the basic equipment requirements for the GMAW process
Aluminum wire
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

16. What is a typical flow rate of CO2 for short circuit transfer?
20 to 200 times per second
Higher 26 to 35 arc volts
5.8 to 12.5 L/min
Spatter problems and poor weld appearance

17. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

18. What does the term GMAW identify?
The time rate of response for the current rise and fall
Gas metal arc welding
Cause flaking - which can clog the liner and contact tube
85%

19. 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
Aluminum wire
Generally not as accurate
Wire feed speed - Voltage control

20. How many times per second does short circuiting take place?
20 to 200 times per second
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry
Spatter problems and poor weld appearance

21. Give a brief description of the GMAW process
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode
If you dont know this check your phone

22. What is the required arc voltage used for short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

23. How are GMAW guns rated?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
By there current carrying capacity
Generally not as accurate
Short- circuiting transfer - Globular transfer - Spray transfer

24. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc

25. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
20 to 200 times per second
The Arc voltage

26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
If you dont know this check your phone
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed - Voltage control
Duty cycle

27. Why is the term GMAW preferred over MIG or MAG?
If you dont know this check your phone
...
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect

28. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder
SMAW - GTAW
15 feet (4.5 meters)

29. When is the metal transferred with short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode

30. What does inductance control?
Higher 26 to 35 arc volts
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
The resistace to electrical current flow increases with it. Causing the electrode to heat

31. What is an advantage of pulsed arc transfer with GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Reducing the gas source pressure to a constant working pressure
Short- circuiting transfer - Globular transfer - Spray transfer
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

32. What is the purpose of the shielding gas used in GMAW?
Puddle fluidity
15 feet (4.5 meters)
Shielding the molten weld metal from atmospheric contamination
To prevent leakage - Carbon Dioxide (CO2)

33. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Reducing the gas source pressure to a constant working pressure
Duty cycle
By there current carrying capacity

34. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
To limit the short circuiting current so that spatter is reduced

35. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Guns
Speed of the feed motor and - starting / stopping electrode feed

36. Draw a typical volt amp curve for a machine that is designed for GMAW
Duty cycle
Generally not as accurate
If you dont know this check your phone
The time rate of response for the current rise and fall

37. What is the effect of too much slope?
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 limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas

38. What does voltage do in an electrical circuit?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas
Constant current (CC)

39. Regulators control_____________ flowmeters SHOW____________.
National Electrical Manufactures Association
The Arc voltage
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas

40. List the factors that determine the mode of metal transfer
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gives arc voltage values to the control system of the feeder
V groove or U groove

41. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
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
Puddle fluidity

42. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
National Electrical Manufactures Association
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...
Higher 26 to 35 arc volts

43. 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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
The negative side of a welding unit

44. What does a flowmeter do and what does it measure?
Insufficient current to melt the wire off cleanly
Constant current (CC)
12 to 22 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle

45. What is the recommended electrode stick- out for .035 solid wire?
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance
The negative side of a welding unit
1/4 inch to 1/2 inch

46. What would be an indication that the drive roll pressure is adjusted correctly?
Constant current (CC)
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)
Pressure - The rate of flow of a shielding gas

47. What are the 2 types of wire feeders available?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
Penetration and burn - off rate of the electrode

48. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders

49. List 3 wire drive systems and give a short description of each
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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

50. What power sources are used with the GMAW Process?
Constant voltage (CV)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs
Shielding the molten weld metal from atmospheric contamination