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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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?
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)
Duty cycle
Generally not as accurate

2. Why is the term GMAW preferred over MIG or MAG?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
The negative side of a welding unit
These terms are quite restrictive and often technically incorrect

3. What controls amperage when using GMAW?
The Arc voltage
20 to 200 times per second
Pressure vessels and the piping industry
Wire feed speed

4. What current and polarity is generally used with GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires

5. What does the wire feeder control?
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input

6. What is the preferred drive roll design for solid wires?
By there current carrying capacity
V groove or U groove
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Duty cycle

7. What type of power source is commonly used with a voltage sensing wire feeder?
3
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Constant current (CC)

8. What type of power source is used with a constant speed wire feeder?
Guns
Constant voltage (CV)
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs

9. What is a typical flow rate of CO2 for short circuit transfer?
15 feet (4.5 meters)
5.8 to 12.5 L/min
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

10. What is the purpose of the shielding gas used in GMAW?
Gas metal arc welding
Voltage is the force that overcomes resistance to allow amperage flow
Shielding the molten weld metal from atmospheric contamination
Spatter problems and poor weld appearance

11. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Cause flaking - which can clog the liner and contact tube

12. What controls the wire speed on a voltage sensing wire 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage
Guns

13. List the factors that determine the mode of metal transfer
Spatter problems and poor weld appearance
The Arc voltage
Puddle fluidity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

14. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly

15. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
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

16. Why is a line heater required when using GMAW?
3
The resistace to electrical current flow increases with it. Causing the electrode to heat
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input

17. What does inductance control?
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)
Flux cored wires
By there current carrying capacity

18. How are GMAW guns rated?
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity
5.8 to 12.5 L/min
Wire feeds smoothly (yet will slip should a problem occur in the gun)

19. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
SMAW - GTAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...

20. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Guns
To limit the short circuiting current so that spatter is reduced
Flux cored wires

21. Give a brief description of the GMAW process
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc

22. List 3 wire drive systems and give a short description of each
AWS and CSA
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage

23. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
By there current carrying capacity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch

24. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
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 does the term GMAW identify?
Gas metal arc welding
When the filler wire is in direct contract with the base metal
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure

26. What is the maximum distance that hard wire can be successfully pushed?
Constant current (CC)
20 to 200 times per second
15 feet (4.5 meters)
Aluminum wire

27. What is the purpose of a regulator and what does it indicate on its gauges?
Wire feed speed - Voltage control
Reducing the gas source pressure to a constant working pressure
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

28. What does a flowmeter do and what does it measure?
Constant current (CC)
Spatter problems and poor weld appearance
Constant voltage (CV)
Controls the rate of flow of a shielding gas to the gun nozzle

29. With straight polarity where is 2/3 of the arc energy?
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect
The negative side of a welding unit
Wire feeds smoothly (yet will slip should a problem occur in the gun)

30. What is the key advantage of short circuiting transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
Spatter problems and poor weld appearance

31. In the GMAW process what does amperage control?
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode

32. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent drawing of liquid CO2 (Carbon Dioxide)
12 to 22 arc volts

33. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding process that joins metals by heating them with an electric arc
The resistace to electrical current flow increases with it. Causing the electrode to heat

34. What wire are knurled drive rolls most commonly used on?
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
Flux cored wires
Generally not as accurate

35. 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
1/4 inch to 1/2 inch

36. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
Minimum distortion due to low heat input
Constant current (CC)
...

37. What does the abbreviation NEMA stand for?
By there current carrying capacity
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)

38. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Spatter problems and poor weld appearance
The Arc voltage
Welding process that joins metals by heating them with an electric arc

39. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The negative side of a welding unit
Generally not as accurate
Penetration and burn - off rate of the electrode
Gives arc voltage values to the control system of the feeder

40. Regulators control_____________ flowmeters SHOW____________.
SMAW - GTAW
V groove or U groove
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas

41. What is an advantage of pulsed arc transfer with GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

42. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

43. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
Flux cored wires

44. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate
The resistace to electrical current flow increases with it. Causing the electrode to heat

45. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
...
Motor driven generators - Transformer rectifiers - and Inverter designs

46. Why is a fiber washer required and what cylinder gas requires it?
Penetration and burn - off rate of the electrode
Constant voltage (CV)
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)

47. When is the metal transferred with short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min

48. Draw a typical volt amp curve for a machine that is designed for GMAW
The Arc voltage
Minimum distortion due to low heat input
If you dont know this check your phone
Gas metal arc welding

49. In the GMAW process what does voltage control?
Welding process that joins metals by heating them with an electric arc
3
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity

50. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
AWS and CSA
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
Flux cored wires