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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 reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
By there current carrying capacity
...
SMAW - GTAW
Generally not as accurate

2. List 3 forms compressed gases may be supplied for welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)
Duty cycle

3. Why is the term GMAW preferred over MIG or MAG?
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect

4. What controls amperage when using GMAW?
Wire feed speed
The negative side of a welding unit
1/4 inch to 1/2 inch
The time rate of response for the current rise and fall

5. What is the required arc voltage used for short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts
Pressure vessels and the piping industry
Insufficient current to melt the wire off cleanly

6. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Minimum distortion due to low heat input
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity

7. In the GMAW process what does voltage control?
Aluminum wire
Puddle fluidity
3
20 to 200 times per second

8. What is the recommended electrode stick- out for .035 solid wire?
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

9. What does the term GMAW identify?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts
Gas metal arc welding
Cause flaking - which can clog the liner and contact tube

10. Why must CO2 cylinders be used in the vertical position?
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry

11. What does voltage do in an electrical circuit?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)

12. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Pressure vessels and the piping industry
(DCEP) Direct Current Electrode Positive or Reverse polarity
3
By there current carrying capacity

13. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Penetration and burn - off rate of the electrode
1/4 inch to 1/2 inch
Pressure vessels and the piping industry

14. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)

15. What output on the welding machine is used to rate the duty cycle?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas

16. What is a solenoid valve and what actuates it?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Higher 26 to 35 arc volts

17. Why is a fiber washer required and what cylinder gas requires it?
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)

18. A 10 minute cycle of welding time vs cooling time a given machine can handle.
If you dont know this check your phone
Duty cycle
When the filler wire is in direct contract with the base metal
SMAW - GTAW

19. What effect does increasing and decreasing the inductance have on the weld?
Wire feed speed
1/4 inch to 1/2 inch
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

20. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
15 feet (4.5 meters)
3
To prevent leakage - Carbon Dioxide (CO2)

21. What 2 controls are found on a GMAW set- up?
SMAW - GTAW
Wire feed speed - Voltage 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
Reducing the gas source pressure to a constant working pressure

22. What current and polarity is generally used with GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity

23. What processes are constant current (CC) power sources designed to be used with?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW
When the filler wire is in direct contract with the base metal

24. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
SMAW - GTAW
Wire feed speed - Voltage control

25. How are GMAW guns rated?
To prevent leakage - Carbon Dioxide (CO2)
The negative side of a welding unit
By there current carrying capacity
Aluminum wire

26. What is the maximum distance that hard wire can be successfully pushed?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Constant current (CC)

27. What is the key advantage of short circuiting transfer?
SMAW - GTAW
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%

28. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder
Insufficient current to melt the wire off cleanly

29. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Insufficient current to melt the wire off cleanly
Cause flaking - which can clog the liner and contact tube
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
...

30. What are the 2 types of wire feeders available?
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Shielding the molten weld metal from atmospheric contamination

31. What would be an indication that the drive roll pressure is adjusted correctly?
Cause flaking - which can clog the liner and contact tube
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
Gives arc voltage values to the control system of the feeder

32. List the factors that determine the mode of metal transfer
Insufficient current to melt the wire off cleanly
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed

33. What does the wire feeder control?
Reducing the gas source pressure to a constant working pressure
Speed of the feed motor and - starting / stopping electrode feed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
20 to 200 times per second

34. What type of power source is commonly used with a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Constant current (CC)
5.8 to 12.5 L/min
3

35. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Generally not as accurate
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

36. What happens when the electrode extension is increased?
Controls the rate of flow of a shielding gas to the gun nozzle
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
...

37. List the basic equipment requirements for the GMAW process
Reducing the gas source pressure to a constant working pressure
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)

38. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Flux cored wires
(DCEP) Direct Current Electrode Positive or Reverse polarity
3
Minutes of elapsed time continually run (out of 10 minutes)

39. What does inductance control?
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat
85%
The time rate of response for the current rise and fall

40. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Flux cored wires
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

41. With straight polarity where is 2/3 of the arc energy?
Higher 26 to 35 arc volts
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The negative side of a welding unit

42. What is the purpose of the shielding gas used in GMAW?
Pressure - The rate of flow of a shielding gas
Shielding the molten weld metal from atmospheric contamination
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

43. List 3 wire drive systems and give a short description of each
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant voltage (CV)
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
Flux cored wires

44. What is a typical flow rate of CO2 for short circuit transfer?
3
The resistace to electrical current flow increases with it. Causing the electrode to heat
5.8 to 12.5 L/min
Wire feed speed

45. Give a description of 'pinch effect'
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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)
Gas metal arc welding

46. List several industries that would use GMAW
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect

47. How many times per second does short circuiting take place?
15 feet (4.5 meters)
V groove or U groove
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

48. What is the preferred drive roll design for solid wires?
Higher 26 to 35 arc volts
Minimum distortion due to low heat input
The negative side of a welding unit
V groove or U groove

49. Regulators control_____________ flowmeters SHOW____________.
Guns
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
Constant voltage (CV)

50. What is an advantage of pulsed arc transfer with GMAW?
To limit the short circuiting current so that spatter is reduced
V groove or U groove
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze