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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 does voltage do in an electrical circuit?
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
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
Duty cycle

2. Why is a line heater required when using GMAW?
5.8 to 12.5 L/min
Dry ice can form within the flow control openings and cause blockage of shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

3. What 2 organizations designate specifications for GMAW wires?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
AWS and CSA

4. 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
...
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
Controls the rate of flow of a shielding gas to the gun nozzle

5. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant voltage (CV)
Higher 26 to 35 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity

6. Why is globular transfer generally avoided with GMAW?
Insufficient current to melt the wire off cleanly
By there current carrying capacity
V groove or U groove
Spatter problems and poor weld appearance

7. What effect does increasing and decreasing the inductance have on the weld?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minimum distortion due to low heat input
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...

8. What is the purpose of a regulator and what does it indicate on its gauges?
AWS and CSA
Reducing the gas source pressure to a constant working pressure
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect

9. List the factors that determine the mode of metal transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
3
When the filler wire is in direct contract with the base metal

10. In the GMAW process what does voltage control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch

11. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
SMAW - GTAW
By there current carrying capacity

12. What happens when the electrode extension is increased?
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
The Arc voltage
The resistace to electrical current flow increases with it. Causing the electrode to heat

13. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant voltage (CV)

14. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Constant voltage (CV)
20 to 200 times per second
3

15. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs

16. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant- speed wire feeders and Voltage- sennsing wire feeders

17. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure vessels and the piping industry
Aluminum wire

18. What power sources are used with the GMAW Process?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

19. What type of power source is commonly used with a voltage sensing wire feeder?
Insufficient current to melt the wire off cleanly
Constant current (CC)
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

20. List several industries that would use GMAW
85%
3
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure vessels and the piping industry

21. What is the effect of too much slope?
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
Insufficient current to melt the wire off cleanly
Gives arc voltage values to the control system of the feeder

22. What controls amperage when using GMAW?
Wire feed speed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode

23. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Wire feed speed
Higher 26 to 35 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect

24. What does a flowmeter do and what does it measure?
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube

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

26. With straight polarity where is 2/3 of the arc energy?
Duty cycle
The negative side of a welding unit
Guns
1/4 inch to 1/2 inch

27. What wire are knurled drive rolls most commonly used on?
AWS and CSA
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires

28. What does the wire feeder control?
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced

29. In the GMAW process what does amperage control?
Guns
Penetration and burn - off rate of the electrode
3
Cause flaking - which can clog the liner and contact tube

30. When is the metal transferred with short circuit transfer?
Aluminum wire
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
Gas metal arc welding

31. What 2 controls are found on a GMAW set- up?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
By there current carrying capacity

32. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Voltage is the force that overcomes resistance to allow amperage flow
(DCEP) Direct Current Electrode Positive or Reverse polarity
15 feet (4.5 meters)
12 to 22 arc volts

33. What type of power source is used with a constant speed wire feeder?
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed
Constant voltage (CV)

34. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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
Duty cycle

35. What is the main purpose of 'slope'?
Higher 26 to 35 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

36. What would be an indication that the drive roll pressure is adjusted correctly?
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gives arc voltage values to the control system of the feeder

37. What does inductance control?
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding
Wire feed speed - Voltage control
The time rate of response for the current rise and fall

38. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Higher 26 to 35 arc volts
By there current carrying capacity
Duty cycle
AWS and CSA

39. What is the preferred drive roll design for solid wires?
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove

40. Why must CO2 cylinders be used in the vertical position?
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)

41. List the basic equipment requirements for the GMAW process
AWS and CSA
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
The resistace to electrical current flow increases with it. Causing the electrode to heat

42. Draw a typical volt amp curve for a machine that is designed for GMAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone
Constant current (CC)

43. What does the abbreviation NEMA stand for?
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity
National Electrical Manufactures Association
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

44. How many times per second does short circuiting take place?
Voltage is the force that overcomes resistance to allow amperage flow
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
Guns

45. How are GMAW guns rated?
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

46. List 3 wire drive systems and give a short description of each
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
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
V groove or U groove

47. What controls the wire speed on a voltage sensing wire feeder?
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage

48. List 3 forms compressed gases may be supplied for welding
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
Short- circuiting transfer - Globular transfer - Spray transfer

49. 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
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
Penetration and burn - off rate of the electrode

50. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
Controls the rate of flow of a shielding gas to the gun nozzle