Test your basic knowledge |

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 inductance control?
The time rate of response for the current rise and fall
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association

2. List the three methods of metal transfer with GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination

3. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant voltage (CV)
Flux cored wires
12 to 22 arc volts
If you dont know this check your phone

4. What current and polarity is generally used with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode

5. What 2 organizations designate specifications for GMAW wires?
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced
Flux cored wires
AWS and CSA

6. List 3 wire drive systems and give a short description of each
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
Penetration and burn - off rate of the electrode
Constant voltage (CV)
Guns

7. Give a brief description of the GMAW process
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

8. What is the recommended electrode stick- out for .035 solid wire?
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
The negative side of a welding unit
85%

9. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
...
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
(DCEP) Direct Current Electrode Positive or Reverse polarity

10. What controls amperage when using GMAW?
Wire feed speed
20 to 200 times per second
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

11. What is another term for electrode holders for GMAW?
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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

12. What type of power source is commonly used with a voltage sensing wire feeder?
The Arc voltage
Constant current (CC)
Spatter problems and poor weld appearance
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

13. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)
National Electrical Manufactures Association

14. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity

15. What controls the wire speed on a voltage sensing wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
AWS and CSA
The Arc voltage
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

16. A pull type drive system is usually used on what type of material?
Generally not as accurate
85%
Gas metal arc welding
Aluminum wire

17. What type of power source is used with a constant speed wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal
The time rate of response for the current rise and fall
Constant voltage (CV)

18. In the GMAW process what does amperage control?
...
SMAW - GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode

19. When is the metal transferred with short circuit transfer?
1/4 inch to 1/2 inch
When the filler wire is in direct contract with the base metal
20 to 200 times per second
Duty cycle

20. What is a typical flow rate of CO2 for short circuit transfer?
Constant current (CC)
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
85%

21. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
20 to 200 times per second
Constant voltage (CV)
Penetration and burn - off rate of the electrode

22. Why must CO2 cylinders be used in the vertical position?
...
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)
To limit the short circuiting current so that spatter is reduced

23. What is the preferred drive roll design for solid wires?
Reducing the gas source pressure to a constant working pressure
Speed of the feed motor and - starting / stopping electrode feed
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

24. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Short- circuiting transfer - Globular transfer - Spray transfer
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
Voltage is the force that overcomes resistance to allow amperage flow

25. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
Pressure - The rate of flow of a shielding gas
3

26. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

27. 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
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc

28. What would be an indication that the drive roll pressure is adjusted correctly?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

29. What is an advantage of pulsed arc transfer with GMAW?
Spatter problems and poor weld appearance
When the filler wire is in direct contract with the base metal
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
Gives arc voltage values to the control system of the feeder
Generally not as accurate

31. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gives arc voltage values to the control system of the feeder
Puddle fluidity

32. What is the maximum distance that hard wire can be successfully pushed?
SMAW - GTAW
15 feet (4.5 meters)
These terms are quite restrictive and often technically incorrect
Spatter problems and poor weld appearance

33. How many times per second does short circuiting take place?
Generally not as accurate
When the filler wire is in direct contract with the base metal
Guns
20 to 200 times per second

34. What is a solenoid valve and what actuates it?
Wire feed speed - Voltage control
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
If you dont know this check your phone

35. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)

36. Why is a fiber washer required and what cylinder gas requires it?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

37. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Gives arc voltage values to the control system of the feeder
Higher 26 to 35 arc volts
Cause flaking - which can clog the liner and contact tube
Generally not as accurate

38. Why is the term GMAW preferred over MIG or MAG?
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)

39. What does the wire feeder control?
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

40. What does the term GMAW identify?
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
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. List the factors that determine the mode of metal transfer
Gas metal arc welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
The Arc voltage

42. What does a flowmeter do and what does it measure?
These terms are quite restrictive and often technically incorrect
Controls the rate of flow of a shielding gas to the gun nozzle
Guns
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

43. What wire are knurled drive rolls most commonly used on?
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed - Voltage control
Flux cored wires

44. List the basic equipment requirements for the GMAW process
Shielding the molten weld metal from atmospheric contamination
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Speed of the feed motor and - starting / stopping electrode feed

45. 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
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly

46. 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
12 to 22 arc volts
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

47. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Insufficient current to melt the wire off cleanly
...
Flux cored wires
The resistace to electrical current flow increases with it. Causing the electrode to heat

48. What is the required arc voltage used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

49. Give a description of 'pinch effect'
When the filler wire is in direct contract with the base metal
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
The Arc voltage

50. What 2 controls are found on a GMAW set- up?
Wire feed speed
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed - Voltage control