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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 are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs

2. A pull type drive system is usually used on what type of material?
Aluminum wire
Duty cycle
Wire feed speed
Minimum distortion due to low heat input

3. What is the purpose of a regulator and what does it indicate on its gauges?
1/4 inch to 1/2 inch
Reducing the gas source pressure to a constant working pressure
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)

4. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Generally not as accurate
By there current carrying capacity
If you dont know this check your phone
Gives arc voltage values to the control system of the feeder

5. What does a flowmeter do and what does it measure?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
(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

6. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
To prevent drawing of liquid CO2 (Carbon Dioxide)
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity

7. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)
3

8. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association
If you dont know this check your phone
Pressure vessels and the piping industry

9. What wire are knurled drive rolls most commonly used on?
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Flux cored wires

10. What is a solenoid valve and what actuates it?
Gives arc voltage values to the control system of the feeder
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
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

11. What power sources are used with the GMAW Process?
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity

12. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Puddle fluidity
...
Welding process that joins metals by heating them with an electric arc

13. List the three methods of metal transfer with GMAW
The Arc voltage
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
National Electrical Manufactures Association

14. Why is the term GMAW preferred over MIG or MAG?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance
15 feet (4.5 meters)
These terms are quite restrictive and often technically incorrect

15. What is the preferred drive roll design for solid wires?
National Electrical Manufactures Association
V groove or U groove
Generally not as accurate
Constant current (CC)

16. List several industries that would use GMAW
Pressure vessels and the piping industry
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
(DCEP) Direct Current Electrode Positive or Reverse polarity

17. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
Flux cored wires
Duty cycle

18. What type of power source is commonly used with a voltage sensing wire feeder?
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)
Guns

19. Regulators control_____________ flowmeters SHOW____________.
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance
Pressure - The rate of flow of a shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

20. What is the purpose of the shielding gas used in GMAW?
Puddle fluidity
The Arc voltage
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders

21. What is the recommended electrode stick- out for .035 solid wire?
Constant current (CC)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding
1/4 inch to 1/2 inch

22. What type of power source is used with a constant speed wire feeder?
Pressure - The rate of flow of a shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure vessels and the piping industry
Constant voltage (CV)

23. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed

24. What controls amperage when using GMAW?
...
85%
Duty cycle
Wire feed speed

25. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA

26. What is the effect of too much slope?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)

27. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit

28. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

29. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control

30. How many times per second does short circuiting take place?
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
SMAW - GTAW

31. Draw a typical volt amp curve for a machine that is designed for GMAW
The time rate of response for the current rise and fall
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent drawing of liquid CO2 (Carbon Dioxide)

32. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
The negative side of a welding unit
Wire feed speed - Voltage control
SMAW - GTAW

33. 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
Gives arc voltage values to the control system of the feeder
85%
Penetration and burn - off rate of the electrode

34. Give a description of 'pinch effect'
Flux cored wires
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Voltage is the force that overcomes resistance to allow amperage flow

35. What would be an indication that the drive roll pressure is adjusted correctly?
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)

36. Why is a line heater required when using GMAW?
Aluminum wire
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Spatter problems and poor weld appearance

37. List the factors that determine the mode of metal transfer
Speed of the feed motor and - starting / stopping electrode feed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

38. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
Wire feed speed
Guns

39. What does voltage do in an electrical circuit?
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow
Constant- speed wire feeders and Voltage- sennsing wire feeders
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

40. What is the required arc voltage used for short circuit transfer?
5.8 to 12.5 L/min
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal

41. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant current (CC)
Controls the rate of flow of a shielding gas to the gun nozzle
Guns

42. What does the term GMAW identify?
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

43. With straight polarity where is 2/3 of the arc energy?
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure - The rate of flow of a shielding gas

44. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
The negative side of a welding unit

45. How are GMAW guns rated?
Constant voltage (CV)
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity

46. Why must CO2 cylinders be used in the vertical position?
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)
To prevent leakage - Carbon Dioxide (CO2)

47. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Insufficient current to melt the wire off cleanly
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity

48. In the GMAW process what does voltage control?
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association
Puddle fluidity
Wire feed speed

49. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Reducing the gas source pressure to a constant working pressure
Higher 26 to 35 arc volts
Duty cycle
1/4 inch to 1/2 inch

50. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)