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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Reducing the gas source pressure to a constant working pressure
V groove or U groove
SMAW - GTAW

2. What is a solenoid valve and what actuates it?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire
Higher 26 to 35 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

3. What output on the welding machine is used to rate the duty cycle?
If you dont know this check your phone
Gas metal arc welding
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)

4. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
15 feet (4.5 meters)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant current (CC)

5. What is the main purpose of 'slope'?
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)

6. What does the term GMAW identify?
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW
Gas metal arc welding

7. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
National Electrical Manufactures Association
Gives arc voltage values to the control system of the feeder
By there current carrying capacity

8. 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
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
85%

9. With straight polarity where is 2/3 of the arc energy?
12 to 22 arc volts
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

10. In the GMAW process what does voltage control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Puddle fluidity
By there current carrying capacity
Gas metal arc welding

11. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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

12. What processes are constant current (CC) power sources designed to be used with?
When the filler wire is in direct contract with the base metal
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas

13. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Aluminum wire
...
Higher 26 to 35 arc volts
3

14. What current and polarity is generally used with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

15. 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
AWS and CSA
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure

16. What effect does increasing and decreasing the inductance have on the weld?
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity

17. Why is the term GMAW preferred over MIG or MAG?
When the filler wire is in direct contract with the base metal
Shielding the molten weld metal from atmospheric contamination
These terms are quite restrictive and often technically incorrect
Flux cored wires

18. What happens when the electrode extension is increased?
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW

19. When is the metal transferred with short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
Flux cored wires
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal

20. Why is a line heater required when using GMAW?
The negative side of a welding unit
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity

21. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Insufficient current to melt the wire off cleanly
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
3

22. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage

23. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders

24. What would be an indication that the drive roll pressure is adjusted correctly?
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
Guns
Wire feeds smoothly (yet will slip should a problem occur in the gun)

25. Regulators control_____________ flowmeters SHOW____________.
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas
Aluminum wire
Minimum distortion due to low heat input

26. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

27. List 3 wire drive systems and give a short description of each
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure
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

28. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
If you dont know this check your phone
Wire feed speed
Generally not as accurate

29. Give a description of 'pinch effect'
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas

30. List the three methods of metal transfer with GMAW
Shielding the molten weld metal from atmospheric contamination
Guns
Short- circuiting transfer - Globular transfer - Spray transfer
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

31. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
85%
Constant current (CC)
Cause flaking - which can clog the liner and contact tube
DCEP (Direct Current Electrode Positive) Reverse Polarity

32. In the GMAW process what does amperage control?
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
Penetration and burn - off rate of the electrode
To limit the short circuiting current so that spatter is reduced

33. What is the key advantage of short circuiting transfer?
Generally not as accurate
20 to 200 times per second
Short- circuiting transfer - Globular transfer - Spray transfer
Minimum distortion due to low heat input

34. What is the preferred drive roll design for solid wires?
Insufficient current to melt the wire off cleanly
12 to 22 arc volts
V groove or U groove
Penetration and burn - off rate of the electrode

35. What type of power source is commonly used with a voltage sensing wire feeder?
Insufficient current to melt the wire off cleanly
Generally not as accurate
Pressure vessels and the piping industry
Constant current (CC)

36. Why is globular transfer generally avoided with GMAW?
The negative side of a welding unit
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Spatter problems and poor weld appearance
85%

37. What is a typical flow rate of CO2 for short circuit transfer?
If you dont know this check your phone
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)
...

38. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Minimum distortion due to low heat input
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch

39. What is an advantage of pulsed arc transfer with GMAW?
The time rate of response for the current rise and fall
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
Constant current (CC)

40. What does inductance control?
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall
The negative side of a welding unit
Reducing the gas source pressure to a constant working pressure

41. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Flux cored wires
When the filler wire is in direct contract with the base metal
Generally not as accurate
Penetration and burn - off rate of the electrode

42. What is another term for electrode holders for GMAW?
Guns
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder
Gas metal arc welding

43. How many times per second does short circuiting take place?
20 to 200 times per second
SMAW - GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect

44. What does voltage do in an electrical circuit?
3
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity

45. What 2 controls are found on a GMAW set- up?
National Electrical Manufactures Association
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
The negative side of a welding unit

46. List several industries that would use GMAW
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect
Voltage is the force that overcomes resistance to allow amperage flow
Controls the rate of flow of a shielding gas to the gun nozzle

47. What controls the wire speed on a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts
Constant current (CC)
The Arc voltage

48. List the factors that determine the mode of metal transfer
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Dry ice can form within the flow control openings and cause blockage of shielding gas

49. What is the purpose of the shielding gas used in GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

50. What are the 2 types of wire feeders available?
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire
Wire feed speed - Voltage control