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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 purpose of a regulator and what does it indicate on its gauges?
20 to 200 times per second
To limit the short circuiting current so that spatter is reduced
Reducing the gas source pressure to a constant working pressure
Cause flaking - which can clog the liner and contact tube

2. What is an advantage of pulsed arc transfer with GMAW?
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
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

3. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Higher 26 to 35 arc volts
If you dont know this check your phone
Duty cycle

4. What is the required arc voltage used for short circuit transfer?
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input
12 to 22 arc volts

5. List several industries that would use GMAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
(DCEP) Direct Current Electrode Positive or Reverse polarity
Puddle fluidity

6. What controls the wire speed on a voltage sensing wire feeder?
The time rate of response for the current rise and fall
The Arc voltage
Constant current (CC)
Spatter problems and poor weld appearance

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Reducing the gas source pressure to a constant working pressure
...
By there current carrying capacity
When the filler wire is in direct contract with the base metal

8. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Reducing the gas source pressure to a constant working pressure
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders

9. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage
Shielding the molten weld metal from atmospheric contamination

10. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
To limit the short circuiting current so that spatter is reduced
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove

11. What does the wire feeder control?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed

12. What controls amperage when using GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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Pressure - The rate of flow of a shielding gas
Wire feed speed

13. How are GMAW guns rated?
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The negative side of a welding unit
AWS and CSA

14. What output on the welding machine is used to rate the duty cycle?
85%
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)
The negative side of a welding unit

15. What does the term GMAW identify?
Gas metal arc welding
Generally not as accurate
Higher 26 to 35 arc volts
20 to 200 times per second

16. What processes are constant current (CC) power sources designed to be used with?
Spatter problems and poor weld appearance
Flux cored wires
Higher 26 to 35 arc volts
SMAW - GTAW

17. Give a description of 'pinch effect'
12 to 22 arc volts
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
Insufficient current to melt the wire off cleanly

18. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer
To limit the short circuiting current so that spatter is reduced

19. What does a flowmeter do and what does it measure?
...
By there current carrying capacity
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry

20. Why is a fiber washer required and what cylinder gas requires it?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

21. What happens when the electrode extension is increased?
Dry ice can form within the flow control openings and cause blockage of shielding gas
When the filler wire is in direct contract with the base metal
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat

22. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc
DCEP (Direct Current Electrode Positive) Reverse Polarity

23. List the basic equipment requirements for the GMAW process
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone
85%

24. Why is globular transfer generally avoided with GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Spatter problems and poor weld appearance
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

25. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant voltage (CV)
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
...

26. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle

27. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders

28. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)
National Electrical Manufactures Association

29. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

30. What is a typical flow rate of CO2 for short circuit transfer?
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min
15 feet (4.5 meters)
Duty cycle

31. In the GMAW process what does voltage control?
V groove or U groove
Puddle fluidity
Wire feed speed
Aluminum wire

32. What power sources are used with the GMAW Process?
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Flux cored wires

33. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
Spatter problems and poor weld appearance

34. What is a solenoid valve and what actuates it?
To prevent leakage - Carbon Dioxide (CO2)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

35. What are the 2 types of wire feeders available?
Duty cycle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders

36. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Minimum distortion due to low heat input
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The time rate of response for the current rise and fall

37. List the three methods of metal transfer with GMAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To limit the short circuiting current so that spatter is reduced
SMAW - GTAW
Short- circuiting transfer - Globular transfer - Spray transfer

38. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Flux cored wires
Duty cycle
To limit the short circuiting current so that spatter is reduced
The time rate of response for the current rise and fall

39. In the GMAW process what does amperage control?
Voltage is the force that overcomes resistance to allow amperage flow
Guns
These terms are quite restrictive and often technically incorrect
Penetration and burn - off rate of the electrode

40. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW

42. What 2 organizations designate specifications for GMAW wires?
National Electrical Manufactures Association
Gives arc voltage values to the control system of the feeder
Spatter problems and poor weld appearance
AWS and CSA

43. What would be an indication that the drive roll pressure is adjusted correctly?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gas metal arc welding

44. 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
If you dont know this check your phone
Constant current (CC)
SMAW - GTAW

45. What is another term for electrode holders for GMAW?
Spatter problems and poor weld appearance
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Guns

46. How many times per second does short circuiting take place?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minimum distortion due to low heat input
20 to 200 times per second

47. List 3 wire drive systems and give a short description of each
Motor driven generators - Transformer rectifiers - and Inverter designs
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
Minimum distortion due to low heat input
To prevent leakage - Carbon Dioxide (CO2)

48. Why is a line heater required when using 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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts

49. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

50. A pull type drive system is usually used on what type of material?
Wire feed speed - Voltage control
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire
If you dont know this check your phone