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 a flowmeter do and what does it measure?
85%
National Electrical Manufactures Association
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

2. Why is the term GMAW preferred over MIG or MAG?
Flux cored wires
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
(DCEP) Direct Current Electrode Positive or Reverse polarity

3. What happens when the electrode extension is increased?
Gives arc voltage values to the control system of the feeder
Constant voltage (CV)
(DCEP) Direct Current Electrode Positive or Reverse polarity
The resistace to electrical current flow increases with it. Causing the electrode to heat

4. What is another term for electrode holders for GMAW?
5.8 to 12.5 L/min
Reducing the gas source pressure to a constant working pressure
The negative side of a welding unit
Guns

5. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Flux cored wires
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns

6. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Controls the rate of flow of a shielding gas to the gun nozzle

7. What does the wire feeder control?
By there current carrying capacity
The time rate of response for the current rise and fall
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)

8. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode

9. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
...

10. What is a solenoid valve and what actuates it?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Higher 26 to 35 arc volts

11. How many times per second does short circuiting take place?
20 to 200 times per second
85%
Voltage is the force that overcomes resistance to allow amperage flow
3

12. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts

13. What is the key advantage of short circuiting transfer?
Wire feed speed - Voltage control
15 feet (4.5 meters)
Spatter problems and poor weld appearance
Minimum distortion due to low heat input

14. How are GMAW guns rated?
By there current carrying capacity
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

15. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
The time rate of response for the current rise and fall
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly

16. What output on the welding machine is used to rate the duty cycle?
Cause flaking - which can clog the liner and contact tube
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry
The negative side of a welding unit

17. Why must CO2 cylinders be used in the vertical position?
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed - Voltage control

18. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant current (CC)
Duty cycle
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

19. What is the maximum distance that hard wire can be successfully pushed?
85%
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)

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
Gas metal arc welding
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

21. What type of power source is commonly used with a voltage sensing wire feeder?
By there current carrying capacity
If you dont know this check your phone
Constant current (CC)
Flux cored wires

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
Pressure - The rate of flow of a shielding gas
V groove or U groove
12 to 22 arc volts

23. List several industries that would use GMAW
Wire feed speed
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
Pressure - The rate of flow of a shielding gas

24. Give a brief description of the GMAW process
V groove or U groove
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit

25. Give a description of 'pinch effect'
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
If you dont know this check your phone
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

26. What processes are constant current (CC) power sources designed to be used with?
15 feet (4.5 meters)
Minimum distortion due to low heat input
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

27. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
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
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

28. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Welding process that joins metals by heating them with an electric arc
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Shielding the molten weld metal from atmospheric contamination

29. What current and polarity is generally used with GMAW?
Welding process that joins metals by heating them with an electric arc
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
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity

30. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Guns
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
Pressure - The rate of flow of a shielding gas

31. What are the 2 types of wire feeders available?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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
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

32. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove
Generally not as accurate
Minimum distortion due to low heat input

33. In the GMAW process what does amperage control?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Penetration and burn - off rate of the electrode
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Short- circuiting transfer - Globular transfer - Spray transfer

34. What effect does increasing and decreasing the inductance have on the weld?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed
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

35. What wire are knurled drive rolls most commonly used on?
(DCEP) Direct Current Electrode Positive or Reverse polarity
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires
Gives arc voltage values to the control system of the feeder

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
The Arc voltage

37. What type of power source is used with a constant speed wire feeder?
1/4 inch to 1/2 inch
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant voltage (CV)
...

38. Draw a typical volt amp curve for a machine that is designed for GMAW
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone

39. 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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle
12 to 22 arc volts

40. What does the term GMAW identify?
SMAW - GTAW
Gas metal arc welding
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

41. Why is a fiber washer required and what cylinder gas requires it?
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)

42. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW
When the filler wire is in direct contract with the base metal
National Electrical Manufactures Association

43. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Wire feed speed - Voltage control
Gives arc voltage values to the control system of the feeder
AWS and CSA

44. A pull type drive system is usually used on what type of material?
Aluminum wire
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 prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow

45. What is the effect of too much slope?
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

46. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association

47. What does voltage do in an electrical circuit?
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
Generally not as accurate
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs

48. 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
Reducing the gas source pressure to a constant working pressure
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

49. List the basic equipment requirements for the GMAW process
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity
To limit the short circuiting current so that spatter is reduced

50. In the GMAW process what does voltage control?
Puddle fluidity
By there current carrying capacity
Gas metal arc welding
Cause flaking - which can clog the liner and contact tube