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 is the main purpose of 'slope'?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
The Arc voltage
Duty cycle

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

3. What is another term for electrode holders for GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Guns
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)

4. What does inductance control?
The time rate of response for the current rise and fall
Generally not as accurate
1/4 inch to 1/2 inch
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. What does the wire feeder control?
Gives arc voltage values to the control system of the feeder
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Controls the rate of flow of a shielding gas to the gun nozzle

6. What current and polarity is generally used with GMAW?
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity

7. What is the maximum distance that hard wire can be successfully pushed?
...
The Arc voltage
15 feet (4.5 meters)
5.8 to 12.5 L/min

8. What effect does increasing and decreasing the inductance have on the weld?
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3

9. What is the purpose of the shielding gas used in GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Shielding the molten weld metal from atmospheric contamination

10. List 3 forms compressed gases may be supplied for welding
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced

11. What controls amperage when using GMAW?
Wire feed speed
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
(DCEP) Direct Current Electrode Positive or Reverse polarity

12. List several industries that would use GMAW
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle
Gives arc voltage values to the control system of the feeder
15 feet (4.5 meters)

13. What 2 organizations designate specifications for GMAW wires?
Flux cored wires
Wire feeds smoothly (yet will slip should a problem occur in the gun)
AWS and CSA
Controls the rate of flow of a shielding gas to the gun nozzle

14. Give a brief description of the GMAW process
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc
Minimum distortion due to low heat input
Guns

15. What is the key advantage of short circuiting transfer?
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
The negative side of a welding unit
Spatter problems and poor weld appearance

16. How many times per second does short circuiting take place?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent drawing of liquid CO2 (Carbon Dioxide)
20 to 200 times per second
Motor driven generators - Transformer rectifiers - and Inverter designs

17. In the GMAW process what does amperage control?
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode
SMAW - GTAW

18. What is the required arc voltage used for short circuit transfer?
Gas metal arc welding
SMAW - GTAW
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)

19. Draw a typical volt amp curve for a machine that is designed for GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
If you dont know this check your phone
Wire feed speed

20. What is the recommended electrode stick- out for .035 solid wire?
Flux cored wires
Constant current (CC)
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

21. Why must CO2 cylinders be used in the vertical position?
85%
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed

22. 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
Short- circuiting transfer - Globular transfer - Spray transfer
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity

23. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
Minimum distortion due to low heat input
Flux cored wires

24. What is an advantage of pulsed arc transfer with GMAW?
Gas metal arc welding
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gives arc voltage values to the control system of the feeder
AWS and CSA

25. List 3 wire drive systems and give a short description of each
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
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
Reducing the gas source pressure to a constant working pressure
DCEP (Direct Current Electrode Positive) Reverse Polarity

26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)
(DCEP) Direct Current Electrode Positive or Reverse polarity
...

27. What output on the welding machine is used to rate the duty cycle?
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly

28. List the factors that determine the mode of metal transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)
20 to 200 times per second

29. What 2 controls are found on a GMAW set- up?
1/4 inch to 1/2 inch
By there current carrying capacity
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
12 to 22 arc volts
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode

31. List the basic equipment requirements for the GMAW process
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)

32. In the GMAW process what does voltage control?
Puddle fluidity
Higher 26 to 35 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire

33. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
The time rate of response for the current rise and fall

34. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts
AWS and CSA
...

35. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
Constant current (CC)

36. What power sources are used with the GMAW Process?
SMAW - GTAW
Voltage is the force that overcomes resistance to allow amperage flow
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs

37. Give a description of 'pinch effect'
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
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow

38. What is the purpose of a regulator and what does it indicate on its gauges?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Aluminum wire
Reducing the gas source pressure to a constant working pressure
Insufficient current to melt the wire off cleanly

39. Why is a fiber washer required and what cylinder gas requires it?
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone

40. What is the preferred drive roll design for solid wires?
AWS and CSA
12 to 22 arc volts
The negative side of a welding unit
V groove or U groove

41. What type of power source is used with a constant speed wire feeder?
To limit the short circuiting current so that spatter is reduced
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)

42. 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
By there current carrying capacity
Wire feed speed - Voltage control
Flux cored wires

43. What would be an indication that the drive roll pressure is adjusted correctly?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow

44. When is the metal transferred with short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
Reducing the gas source pressure to a constant working pressure
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

45. Regulators control_____________ flowmeters SHOW____________.
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas
Generally not as accurate
The time rate of response for the current rise and fall

46. What does voltage do in an electrical circuit?
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
85%

47. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal

48. What are the 2 types of wire feeders available?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders

49. A pull type drive system is usually used on what type of material?
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
85%
Aluminum wire

50. What does the abbreviation NEMA stand for?
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
15 feet (4.5 meters)
National Electrical Manufactures Association