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. List the three methods of metal transfer with GMAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Cause flaking - which can clog the liner and contact tube

2. What does inductance control?
The time rate of response for the current rise and fall
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed
Penetration and burn - off rate of the electrode

3. What controls amperage when using GMAW?
Duty cycle
Wire feed speed
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)

4. What type of power source is commonly used with a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Penetration and burn - off rate of the electrode
Constant current (CC)
The resistace to electrical current flow increases with it. Causing the electrode to heat

5. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Spatter problems and poor weld appearance
...
3
Dry ice can form within the flow control openings and cause blockage of shielding gas

6. A pull type drive system is usually used on what type of material?
Aluminum wire
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
Penetration and burn - off rate of the electrode
Wire feed speed

8. What does a flowmeter do and what does it measure?
Higher 26 to 35 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone

9. 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
Gives arc voltage values to the control system of the feeder
Reducing the gas source pressure to a constant working pressure
...

10. What does the wire feeder control?
Pressure vessels and the piping industry
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas

11. List several industries that would use GMAW
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry
Insufficient current to melt the wire off cleanly
Flux cored wires

12. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate
By there current carrying capacity

13. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas

14. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
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
AWS and CSA

15. When is the metal transferred with short circuit transfer?
Gas metal arc welding
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal
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. What does voltage do in an electrical circuit?
The time rate of response for the current rise and fall
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow

17. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
20 to 200 times per second
Motor driven generators - Transformer rectifiers - and Inverter designs
85%
Generally not as accurate

18. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs

19. What is the purpose of the shielding gas used in GMAW?
12 to 22 arc volts
85%
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)

20. What effect does increasing and decreasing the inductance have on the weld?
The time rate of response for the current rise and fall
Dry ice can form within the flow control openings and cause blockage of shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

21. What are the 2 types of wire feeders available?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
V groove or U groove
Insufficient current to melt the wire off cleanly

22. 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
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode
20 to 200 times per second

23. What is the main purpose of 'slope'?
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)
Speed of the feed motor and - starting / stopping electrode feed

24. Why must CO2 cylinders be used in the vertical position?
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
Motor driven generators - Transformer rectifiers - and Inverter designs

25. 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
5.8 to 12.5 L/min
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

26. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube

27. What output on the welding machine is used to rate the duty cycle?
...
Minutes of elapsed time continually run (out of 10 minutes)
Reducing the gas source pressure to a constant working pressure
Constant current (CC)

28. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Constant current (CC)
DCEP (Direct Current Electrode Positive) Reverse Polarity
...

29. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)
DCEP (Direct Current Electrode Positive) Reverse Polarity

30. What 2 controls are found on a GMAW set- up?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control

31. Why is a line heater required when using GMAW?
AWS and CSA
Penetration and burn - off rate of the electrode
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

32. A 10 minute cycle of welding time vs cooling time a given machine can handle.
These terms are quite restrictive and often technically incorrect
Duty cycle
Generally not as accurate
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

33. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
V groove or U groove
Controls the rate of flow of a shielding gas to the gun nozzle
Flux cored wires
Higher 26 to 35 arc volts

34. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
3

35. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
...
By there current carrying capacity
12 to 22 arc volts

36. What processes are constant current (CC) power sources designed to be used with?
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
SMAW - GTAW

37. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Voltage is the force that overcomes resistance to allow amperage flow
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Generally not as accurate

38. List the basic equipment requirements for the GMAW process
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Higher 26 to 35 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Reducing the gas source pressure to a constant working pressure

39. What controls the wire speed on a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Voltage is the force that overcomes resistance to allow amperage flow
(DCEP) Direct Current Electrode Positive or Reverse polarity
The Arc voltage

40. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
Guns

41. What 2 organizations designate specifications for GMAW wires?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...
AWS and CSA
The time rate of response for the current rise and fall

42. How many times per second does short circuiting take place?
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
SMAW - GTAW
20 to 200 times per second

43. What is the purpose of a regulator and what does it indicate on its gauges?
Dry ice can form within the flow control openings and cause blockage of shielding gas
(DCEP) Direct Current Electrode Positive or Reverse polarity
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW

44. In the GMAW process what does voltage control?
Puddle fluidity
By there current carrying capacity
Generally not as accurate
12 to 22 arc volts

45. Draw a typical volt amp curve for a machine that is designed for GMAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Duty cycle
If you dont know this check your phone
Flux cored wires

46. How are GMAW guns rated?
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
By there current carrying capacity
Aluminum wire
5.8 to 12.5 L/min

47. List 3 forms compressed gases may be supplied for welding
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

48. What is a typical flow rate of CO2 for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly
5.8 to 12.5 L/min

49. Why is the term GMAW preferred over MIG or MAG?
Guns
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch
Wire feeds smoothly (yet will slip should a problem occur in the gun)

50. What would be an indication that the drive roll pressure is adjusted correctly?
Flux cored wires
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)
If you dont know this check your phone