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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'?
Wire feed speed
Generally not as accurate
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal

2. What power sources are used with the GMAW Process?
When the filler wire is in direct contract with the base metal
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Motor driven generators - Transformer rectifiers - and Inverter designs

3. List 3 forms compressed gases may be supplied for welding
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
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

4. What controls amperage when using GMAW?
Higher 26 to 35 arc volts
SMAW - GTAW
V groove or U groove
Wire feed speed

5. What is the purpose of the shielding gas used in GMAW?
Constant current (CC)
Puddle fluidity
Pressure vessels and the piping industry
Shielding the molten weld metal from atmospheric contamination

6. With straight polarity where is 2/3 of the arc energy?
Speed of the feed motor and - starting / stopping electrode feed
V groove or U groove
The negative side of a welding unit
Spatter problems and poor weld appearance

7. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal

8. In the GMAW process what does amperage control?
The negative side of a welding unit
Penetration and burn - off rate of the electrode
By there current carrying capacity
Wire feed speed

9. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Aluminum wire
Duty cycle
5.8 to 12.5 L/min
Insufficient current to melt the wire off cleanly

10. What is the purpose of a regulator and what does it indicate on its gauges?
AWS and CSA
Reducing the gas source pressure to a constant working pressure
85%
Short- circuiting transfer - Globular transfer - Spray transfer

11. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
15 feet (4.5 meters)
85%
20 to 200 times per second

12. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone

13. In the GMAW process what does voltage control?
Wire feed speed
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity

14. List several industries that would use GMAW
...
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal
Pressure vessels and the piping industry

15. What happens when the electrode extension is increased?
12 to 22 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

16. What type of power source is used with a constant speed wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

17. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
V groove or U groove

18. What processes are constant current (CC) power sources designed to be used with?
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube
SMAW - GTAW
These terms are quite restrictive and often technically incorrect

19. What controls the wire speed on a voltage sensing wire feeder?
Speed of the feed motor and - starting / stopping electrode feed
V groove or U groove
The negative side of a welding unit
The Arc voltage

20. What effect does increasing and decreasing the inductance have on the weld?
5.8 to 12.5 L/min
Wire feed speed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
AWS and CSA

21. What does the wire feeder control?
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
Motor driven generators - Transformer rectifiers - and Inverter designs
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

22. What does a flowmeter do and what does it measure?
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts
15 feet (4.5 meters)
Controls the rate of flow of a shielding gas to the gun nozzle

23. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Gives arc voltage values to the control system of the feeder
...
By there current carrying capacity

24. Why is globular transfer generally avoided with GMAW?
When the filler wire is in direct contract with the base metal
Wire feed speed
Spatter problems and poor weld appearance
The resistace to electrical current flow increases with it. Causing the electrode to heat

25. Give a description of 'pinch effect'
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage

26. When is the metal transferred with short circuit transfer?
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal

27. What 2 organizations designate specifications for GMAW wires?
Guns
AWS and CSA
Welding process that joins metals by heating them with an electric arc
Puddle fluidity

28. List the three methods of metal transfer with GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs

29. What are the 2 types of wire feeders available?
If you dont know this check your phone
Constant current (CC)
Higher 26 to 35 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders

30. How are GMAW guns rated?
Constant voltage (CV)
Aluminum wire
By there current carrying capacity
Short- circuiting transfer - Globular transfer - Spray transfer

31. Why is a line heater required when using GMAW?
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
The time rate of response for the current rise and fall
Higher 26 to 35 arc volts

32. Draw a typical volt amp curve for a machine that is designed for GMAW
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone

33. What does the abbreviation NEMA stand for?
V groove or U groove
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity

34. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube
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

35. Why is the term GMAW preferred over MIG or MAG?
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect

36. What is the required arc voltage used for short circuit transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
...

37. What is a typical flow rate of CO2 for short circuit transfer?
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
5.8 to 12.5 L/min

38. What does the term GMAW identify?
These terms are quite restrictive and often technically incorrect
Gas metal arc welding
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)

39. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Duty cycle
...
Constant- speed wire feeders and Voltage- sennsing wire feeders
3

40. Regulators control_____________ flowmeters SHOW____________.
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. What does voltage do in an electrical circuit?
12 to 22 arc volts
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow

42. What wire are knurled drive rolls most commonly used on?
Flux cored wires
National Electrical Manufactures Association
3
(DCEP) Direct Current Electrode Positive or Reverse polarity

43. What does inductance control?
National Electrical Manufactures Association
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall
Constant voltage (CV)

44. What is the preferred drive roll design for solid wires?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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)
V groove or U groove

45. How many times per second does short circuiting take place?
The Arc voltage
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second
AWS and CSA

46. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode

47. What is another term for electrode holders for GMAW?
Guns
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc
Spatter problems and poor weld appearance

48. Why must CO2 cylinders be used in the vertical position?
Voltage is the force that overcomes resistance to allow amperage flow
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)

49. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

50. List 3 wire drive systems and give a short description of each
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Duty cycle
The Arc voltage