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. In the GMAW process what does voltage control?
Puddle fluidity
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas

2. When is the metal transferred with short circuit transfer?
Duty cycle
The Arc voltage
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
When the filler wire is in direct contract with the base metal

3. Why must CO2 cylinders be used in the vertical position?
The Arc voltage
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone

4. What is another term for electrode holders for GMAW?
These terms are quite restrictive and often technically incorrect
Guns
85%
Minutes of elapsed time continually run (out of 10 minutes)

5. Why is a line heater required when using GMAW?
AWS and CSA
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas

6. List the basic equipment requirements for the GMAW process
If you dont know this check your phone
Minimum distortion due to low heat input
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)

7. What does the wire feeder control?
If you dont know this check your phone
Speed of the feed motor and - starting / stopping electrode feed
20 to 200 times per second
Wire feeds smoothly (yet will slip should a problem occur in the gun)

8. Why is the term GMAW preferred over MIG or MAG?
Motor driven generators - Transformer rectifiers - and Inverter designs
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
Flux cored wires

9. List the factors that determine the mode of metal transfer
Speed of the feed motor and - starting / stopping electrode feed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Generally not as accurate
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

10. What processes are constant current (CC) power sources designed to be used with?
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW

11. What controls the wire speed on a voltage sensing wire feeder?
V groove or U groove
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
The Arc voltage

12. What does voltage do in an electrical circuit?
Short- circuiting transfer - Globular transfer - Spray transfer
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
DCEP (Direct Current Electrode Positive) Reverse Polarity

13. What is the recommended electrode stick- out for .035 solid wire?
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To limit the short circuiting current so that spatter is reduced

14. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
...
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed

15. What are the 2 types of wire feeders available?
Higher 26 to 35 arc volts
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
Constant- speed wire feeders and Voltage- sennsing wire feeders

16. What is the maximum distance that hard wire can be successfully pushed?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)

17. 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
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect
By there current carrying capacity

18. Why is a fiber washer required and what cylinder gas requires it?
Guns
To prevent leakage - Carbon Dioxide (CO2)
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

19. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Short- circuiting transfer - Globular transfer - Spray transfer
3
The Arc voltage

20. What wire are knurled drive rolls most commonly used on?
Aluminum wire
Flux cored wires
If you dont know this check your phone
Puddle fluidity

21. With straight polarity where is 2/3 of the arc energy?
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
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
The negative side of a welding unit

22. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
Motor driven generators - Transformer rectifiers - and Inverter designs
Puddle fluidity

23. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
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
85%
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

24. Give a brief description of the GMAW process
To prevent drawing of liquid CO2 (Carbon Dioxide)
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate
Welding process that joins metals by heating them with an electric arc

25. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
12 to 22 arc volts
Pressure vessels and the piping industry
V groove or U groove

26. What is the preferred drive roll design for solid wires?
V groove or U groove
Shielding the molten weld metal from atmospheric contamination
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA

27. What is the disadvantage of the gauge preset type of regulator/flowmeter?
5.8 to 12.5 L/min
Generally not as accurate
The negative side of a welding unit
85%

28. What is an advantage of pulsed arc transfer with GMAW?
12 to 22 arc volts
Generally not as accurate
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent leakage - Carbon Dioxide (CO2)

29. What is the effect of too much slope?
Controls the rate of flow of a shielding gas to the gun nozzle
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
AWS and CSA

30. Regulators control_____________ flowmeters SHOW____________.
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas
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

31. What is the purpose of a regulator and what does it indicate on its gauges?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Reducing the gas source pressure to a constant working pressure
V groove or U groove
3

32. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts
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

33. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

34. What does inductance control?
12 to 22 arc volts
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder

35. What current and polarity is generally used with GMAW?
Guns
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What is the key advantage of short circuiting transfer?
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube

37. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant voltage (CV)

38. Give a description of 'pinch effect'
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
Spatter problems and poor weld appearance
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

39. What is a typical flow rate of CO2 for short circuit transfer?
Guns
Constant voltage (CV)
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat

40. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle

41. What is the main purpose of 'slope'?
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed

42. What output on the welding machine is used to rate the duty cycle?
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
Reducing the gas source pressure to a constant working pressure

43. What is a solenoid valve and what actuates it?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Flux cored wires
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

44. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts

45. How are GMAW guns rated?
Constant current (CC)
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
By there current carrying capacity

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
...
Pressure vessels and the piping industry
Higher 26 to 35 arc volts

47. How many times per second does short circuiting take place?
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
20 to 200 times per second
Constant current (CC)

48. What is the required arc voltage used for short circuit transfer?
AWS and CSA
12 to 22 arc volts
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode

49. What type of power source is commonly used with a voltage sensing wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
By there current carrying capacity
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow

50. A 10 minute cycle of welding time vs cooling time a given machine can handle.
The negative side of a welding unit
Constant voltage (CV)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle