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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. Why is globular transfer generally avoided with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure
Wire feed speed

2. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Penetration and burn - off rate of the electrode
Pressure - The rate of flow of a shielding gas
85%

3. What is a typical flow rate of CO2 for short circuit transfer?
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
5.8 to 12.5 L/min

4. Regulators control_____________ flowmeters SHOW____________.
Penetration and burn - off rate of the electrode
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance

5. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW
Gives arc voltage values to the control system of the feeder

6. What is an advantage of pulsed arc transfer with GMAW?
Aluminum wire
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

7. What does a flowmeter do and what does it measure?
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
Controls the rate of flow of a shielding gas to the gun nozzle
Higher 26 to 35 arc volts

8. How many times per second does short circuiting take place?
AWS and CSA
Flux cored wires
Aluminum wire
20 to 200 times per second

9. What 2 controls are found on a GMAW set- up?
These terms are quite restrictive and often technically incorrect
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control

10. What does inductance control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Reducing the gas source pressure to a constant working pressure
20 to 200 times per second
The time rate of response for the current rise and fall

11. What is the disadvantage of the gauge preset type of regulator/flowmeter?
The Arc voltage
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
Gas metal arc welding

12. What is the effect of too much slope?
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity

13. What wire are knurled drive rolls most commonly used on?
Wire feed speed - Voltage control
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)

14. What current and polarity is generally used with GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Spatter problems and poor weld appearance
DCEP (Direct Current Electrode Positive) Reverse Polarity
The time rate of response for the current rise and fall

15. What is the maximum distance that hard wire can be successfully pushed?
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
V groove or U groove
Welding process that joins metals by heating them with an electric arc

16. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Guns
3
Pressure vessels and the piping industry
The negative side of a welding unit

17. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
The time rate of response for the current rise and fall
If you dont know this check your phone
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

18. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

19. List the basic equipment requirements for the GMAW process
12 to 22 arc volts
Reducing the gas source pressure to a constant working pressure
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

20. What effect does increasing and decreasing the inductance have on the weld?
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

21. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant voltage (CV)
If you dont know this check your phone
The resistace to electrical current flow increases with it. Causing the electrode to heat

22. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Guns
20 to 200 times per second

23. In the GMAW process what does amperage control?
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode

24. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
...
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity

25. What does the term GMAW identify?
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
Gas metal arc welding
85%

26. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Short- circuiting transfer - Globular transfer - Spray transfer
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect

27. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Reducing the gas source pressure to a constant working pressure
Constant current (CC)

28. List the three methods of metal transfer with GMAW
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer

29. What is the purpose of a regulator and what does it indicate on its gauges?
The Arc voltage
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure
V groove or U groove

30. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%
By there current carrying capacity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

31. Why is a fiber washer required and what cylinder gas requires it?
1/4 inch to 1/2 inch
To prevent leakage - Carbon Dioxide (CO2)
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

32. A 10 minute cycle of welding time vs cooling time a given machine can handle.
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle
AWS and CSA
1/4 inch to 1/2 inch

33. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

34. What is the preferred drive roll design for solid wires?
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)

35. What happens when the electrode extension is increased?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Generally not as accurate
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA

36. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs
85%

37. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns

38. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Generally not as accurate
Wire feed speed - Voltage control
DCEP (Direct Current Electrode Positive) Reverse Polarity
Cause flaking - which can clog the liner and contact tube

39. What type of power source is used with a constant speed wire feeder?
Higher 26 to 35 arc volts
Constant voltage (CV)
National Electrical Manufactures Association
The time rate of response for the current rise and fall

40. What is another term for electrode holders for GMAW?
Guns
Aluminum wire
AWS and CSA
National Electrical Manufactures Association

41. List the factors that determine the mode of metal transfer
Duty cycle
Constant voltage (CV)
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

42. How are GMAW guns rated?
Short- circuiting transfer - Globular transfer - Spray transfer
By there current carrying capacity
Flux cored wires
Minimum distortion due to low heat input

43. What 2 organizations designate specifications for GMAW wires?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA
When the filler wire is in direct contract with the base metal
3

44. What is the recommended electrode stick- out for .035 solid wire?
The negative side of a welding unit
1/4 inch to 1/2 inch
Guns
Gives arc voltage values to the control system of the feeder

45. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
Constant voltage (CV)
Welding process that joins metals by heating them with an electric arc

46. Give a description of 'pinch effect'
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

47. A pull type drive system is usually used on what type of material?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall
Generally not as accurate
Aluminum wire

48. What does the wire feeder control?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer

49. What is the purpose of the shielding gas used in GMAW?
15 feet (4.5 meters)
Gas metal arc welding
Generally not as accurate
Shielding the molten weld metal from atmospheric contamination

50. What is a solenoid valve and what actuates it?
By there current carrying capacity
The time rate of response for the current rise and fall
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Dry ice can form within the flow control openings and cause blockage of shielding gas