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. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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 - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone

2. In the GMAW process what does voltage control?
Puddle fluidity
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires

3. List several industries that would use GMAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry

4. What output on the welding machine is used to rate the duty cycle?
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. In the GMAW process what does amperage control?
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode
...
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

6. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
85%
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube

7. What does the wire feeder control?
SMAW - GTAW
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Speed of the feed motor and - starting / stopping electrode feed

8. What controls amperage when using GMAW?
Penetration and burn - off rate of the electrode
Wire feed speed
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts

9. What would be an indication that the drive roll pressure is adjusted correctly?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

10. What effect does increasing and decreasing the inductance have on the weld?
The time rate of response for the current rise and fall
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
Speed of the feed motor and - starting / stopping electrode feed

11. Give a brief description of the GMAW process
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
Gas metal arc welding
Higher 26 to 35 arc volts

12. What type of power source is used with a constant speed wire feeder?
To limit the short circuiting current so that spatter is reduced
V groove or U groove
Constant voltage (CV)
...

13. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
3
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc

14. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
...
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

15. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%

16. What happens when the electrode extension is increased?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)
Generally not as accurate
The resistace to electrical current flow increases with it. Causing the electrode to heat

17. What is a solenoid valve and what actuates it?
The time rate of response for the current rise and fall
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent leakage - Carbon Dioxide (CO2)

18. What 2 controls are found on a GMAW set- up?
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Dry ice can form within the flow control openings and cause blockage of shielding gas

19. What power sources are used with the GMAW Process?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The Arc voltage
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs

20. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
Controls the rate of flow of a shielding gas to the gun nozzle
SMAW - GTAW

21. 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
SMAW - GTAW
The Arc voltage
Gives arc voltage values to the control system of the feeder

22. Regulators control_____________ flowmeters SHOW____________.
Reducing the gas source pressure to a constant working pressure
Pressure - The rate of flow of a shielding gas
Higher 26 to 35 arc volts
Constant current (CC)

23. What does voltage do in an electrical circuit?
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
Reducing the gas source pressure to a constant working pressure
15 feet (4.5 meters)

24. List the three methods of metal transfer with GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs

25. What is the preferred drive roll design for solid wires?
V groove or U groove
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Minimum distortion due to low heat input

26. What is the required arc voltage used for short circuit transfer?
5.8 to 12.5 L/min
Puddle fluidity
Guns
12 to 22 arc volts

27. Why is the term GMAW preferred over MIG or MAG?
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination

28. How many times per second does short circuiting take place?
These terms are quite restrictive and often technically incorrect
Aluminum wire
20 to 200 times per second
National Electrical Manufactures Association

29. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
If you dont know this check your phone
Wire feed speed - Voltage control
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
Gives arc voltage values to the control system of the feeder

30. What does a flowmeter do and what does it measure?
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA
National Electrical Manufactures Association

31. Why is a line heater required when using GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire

32. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall

33. What is an advantage of pulsed arc transfer with GMAW?
To limit the short circuiting current so that spatter is reduced
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

34. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

35. List the basic equipment requirements for 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
20 to 200 times per second
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

36. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow

37. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle

38. Why is a fiber washer required and what cylinder gas requires it?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode
To prevent leakage - Carbon Dioxide (CO2)

39. What is the key advantage of short circuiting transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant voltage (CV)
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube

40. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube

41. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Speed of the feed motor and - starting / stopping electrode feed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

42. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
Speed of the feed motor and - starting / stopping electrode feed
15 feet (4.5 meters)

43. List the factors that determine the mode of metal transfer
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
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

44. What wire are knurled drive rolls most commonly used on?
Constant current (CC)
Flux cored wires
15 feet (4.5 meters)
Higher 26 to 35 arc volts

45. What is another term for electrode holders for GMAW?
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Guns

46. What is the purpose of the shielding gas used in GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination

47. What is the maximum distance that hard wire can be successfully pushed?
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders
15 feet (4.5 meters)

48. What is the main purpose of 'slope'?
Generally not as accurate
The Arc voltage
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input

49. What does the term GMAW identify?
Gas metal arc welding
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
Generally not as accurate

50. What are the 2 types of wire feeders available?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders
Pressure - The rate of flow of a shielding gas