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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 effect does increasing and decreasing the inductance have on the weld?
Guns
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
20 to 200 times per second

2. What does the term GMAW identify?
Gas metal arc welding
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

3. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min
Motor driven generators - Transformer rectifiers - and Inverter designs

4. What is the preferred drive roll design for solid wires?
V groove or U groove
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube

5. What is the disadvantage of the gauge preset type of regulator/flowmeter?
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity

6. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
...
Higher 26 to 35 arc volts
Pressure vessels and the piping industry

7. What processes are constant current (CC) power sources designed to be used with?
By there current carrying capacity
...
SMAW - GTAW
Guns

8. What controls amperage when using GMAW?
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat

9. What happens when the electrode extension is increased?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed - Voltage control
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat

10. List several industries that would use GMAW
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
Pressure vessels and the piping industry
The resistace to electrical current flow increases with it. Causing the electrode to heat

11. Why is a line heater required when using GMAW?
Constant current (CC)
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Dry ice can form within the flow control openings and cause blockage of shielding gas

12. What are the 2 types of wire feeders available?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association

13. What is the effect of too much slope?
12 to 22 arc volts
20 to 200 times per second
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly

14. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
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
Generally not as accurate
Penetration and burn - off rate of the electrode

15. Regulators control_____________ flowmeters SHOW____________.
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
20 to 200 times per second

16. Give a description of 'pinch effect'
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

17. What is the maximum distance that hard wire can be successfully pushed?
Short- circuiting transfer - Globular transfer - Spray transfer
12 to 22 arc volts
3
15 feet (4.5 meters)

18. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect

19. What type of power source is used with a constant speed wire feeder?
Aluminum wire
Wire feed speed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)

20. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
15 feet (4.5 meters)
Motor driven generators - Transformer rectifiers - and Inverter designs

21. Why must CO2 cylinders be used in the vertical position?
Gives arc voltage values to the control system of the feeder
To prevent drawing of liquid CO2 (Carbon Dioxide)
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second

22. A pull type drive system is usually used on what type of material?
Gas metal arc welding
Generally not as accurate
Aluminum wire
By there current carrying capacity

23. What wire are knurled drive rolls most commonly used on?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires
The time rate of response for the current rise and fall
The negative side of a welding unit

24. In the GMAW process what does voltage control?
Gas metal arc welding
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Motor driven generators - Transformer rectifiers - and Inverter designs

25. List the basic equipment requirements for the GMAW process
The negative side of a welding unit
Cause flaking - which can clog the liner and contact tube
Welding process that joins metals by heating them with an electric arc
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

26. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Minimum distortion due to low heat input
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

27. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure vessels and the piping industry
Flux cored wires
If you dont know this check your phone

28. What current and polarity is generally used with GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity
Duty cycle
Insufficient current to melt the wire off cleanly

29. List the factors that determine the mode of metal transfer
Higher 26 to 35 arc volts
Insufficient current to melt the wire off cleanly
1/4 inch to 1/2 inch
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

30. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
If you dont know this check your phone
Flux cored wires
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association

31. What is a typical flow rate of CO2 for short circuit transfer?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure vessels and the piping industry
5.8 to 12.5 L/min
Flux cored wires

32. 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
Gives arc voltage values to the control system of the feeder
Constant- speed wire feeders and Voltage- sennsing wire feeders

33. What does a flowmeter do and what does it measure?
Gives arc voltage values to the control system of the feeder
12 to 22 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
...

34. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Aluminum wire
20 to 200 times per second

35. What does inductance control?
If you dont know this check your phone
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall

36. What is a solenoid valve and what actuates it?
Penetration and burn - off rate of the electrode
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association

37. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant voltage (CV)

38. With straight polarity where is 2/3 of the arc energy?
Spatter problems and poor weld appearance
85%
The negative side of a welding unit
Controls the rate of flow of a shielding gas to the gun nozzle

39. List the three methods of metal transfer with GMAW
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle

40. Why is the term GMAW preferred over MIG or MAG?
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Puddle fluidity
85%

41. Draw a typical volt amp curve for a machine that is designed for GMAW
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association
If you dont know this check your phone
The Arc voltage

42. What is the purpose of a regulator and what does it indicate on its gauges?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Reducing the gas source pressure to a constant working pressure
85%
5.8 to 12.5 L/min

43. When is the metal transferred with short circuit transfer?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
When the filler wire is in direct contract with the base metal

44. A 10 minute cycle of welding time vs cooling time a given machine can handle.
15 feet (4.5 meters)
Generally not as accurate
Duty cycle
Pressure vessels and the piping industry

45. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent drawing of liquid CO2 (Carbon Dioxide)
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%

46. What would be an indication that the drive roll pressure is adjusted correctly?
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
1/4 inch to 1/2 inch
3

47. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity
Short- circuiting transfer - Globular transfer - Spray transfer

48. List 3 wire drive systems and give a short description of each
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
12 to 22 arc volts

49. List 3 forms compressed gases may be supplied for welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

50. What is an advantage of pulsed arc transfer with GMAW?
Cause flaking - which can clog the liner and contact tube
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
3