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. Why is a line heater required when using GMAW?
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

2. What does the term GMAW identify?
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc
Duty cycle

3. 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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat

4. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Constant voltage (CV)
20 to 200 times per second
Guns

5. What does the abbreviation NEMA stand for?
Generally not as accurate
Minimum distortion due to low heat input
National Electrical Manufactures Association
5.8 to 12.5 L/min

6. Draw a typical volt amp curve for a machine that is designed for GMAW
The time rate of response for the current rise and fall
If you dont know this check your phone
1/4 inch to 1/2 inch
Guns

7. What controls amperage when using GMAW?
Duty cycle
Aluminum wire
Generally not as accurate
Wire feed speed

8. List the basic equipment requirements for the GMAW process
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

9. What controls the wire speed on a voltage sensing wire feeder?
Pressure vessels and the piping industry
The Arc voltage
When the filler wire is in direct contract with the base metal
Wire feed speed - Voltage control

10. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Minutes of elapsed time continually run (out of 10 minutes)
Voltage is the force that overcomes resistance to allow amperage flow
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

11. What would be an indication that the drive roll pressure is adjusted correctly?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
Wire feeds smoothly (yet will slip should a problem occur in the gun)

12. What current and polarity is generally used with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
DCEP (Direct Current Electrode Positive) Reverse Polarity
...

13. How are GMAW guns rated?
By there current carrying capacity
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The time rate of response for the current rise and fall

14. Why is globular transfer generally avoided with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance

15. What does a flowmeter do and what does it measure?
When the filler wire is in direct contract with the base metal
Wire feed speed - Voltage control
Controls the rate of flow of a shielding gas to the gun nozzle
Puddle fluidity

16. List 3 wire drive systems and give a short description of each
Constant current (CC)
Minutes of elapsed time continually run (out of 10 minutes)
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

17. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

18. What is the key advantage of short circuiting transfer?
National Electrical Manufactures Association
1/4 inch to 1/2 inch
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
85%
Aluminum wire
Spatter problems and poor weld appearance

20. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
SMAW - GTAW
If you dont know this check your phone
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. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
5.8 to 12.5 L/min
Puddle fluidity

22. What 2 controls are found on a GMAW set- up?
Guns
85%
Spatter problems and poor weld appearance
Wire feed speed - Voltage control

23. What does the wire feeder control?
Duty cycle
Speed of the feed motor and - starting / stopping electrode feed
85%
These terms are quite restrictive and often technically incorrect

24. What is an advantage of pulsed arc transfer with GMAW?
Constant voltage (CV)
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
Short- circuiting transfer - Globular transfer - Spray transfer

25. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Duty cycle
Wire feed speed

26. How many times per second does short circuiting take place?
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
20 to 200 times per second

27. Give a brief description of the GMAW process
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
The time rate of response for the current rise and fall

28. What output on the welding machine is used to rate the duty cycle?
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed
Duty cycle

29. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity
Puddle fluidity
The negative side of a welding unit

30. What is the purpose of a regulator and what does it indicate on its gauges?
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage

31. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
Generally not as accurate
AWS and CSA

32. In the GMAW process what does amperage control?
Reducing the gas source pressure to a constant working pressure
The resistace to electrical current flow increases with it. Causing the electrode to heat
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode

33. When is the metal transferred with short circuit transfer?
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
When the filler wire is in direct contract with the base metal
Higher 26 to 35 arc volts

34. 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
Aluminum wire
The negative side of a welding unit
Gas metal arc welding

35. What type of power source is used with a constant speed wire feeder?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant voltage (CV)
If you dont know this check your phone
Penetration and burn - off rate of the electrode

36. What is the recommended electrode stick- out for .035 solid wire?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Controls the rate of flow of a shielding gas to the gun nozzle
...
1/4 inch to 1/2 inch

37. In the GMAW process what does voltage control?
Penetration and burn - off rate of the electrode
The negative side of a welding unit
Puddle fluidity
AWS and CSA

38. List 3 forms compressed gases may be supplied for welding
If you dont know this check your phone
Minimum distortion due to low heat input
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Motor driven generators - Transformer rectifiers - and Inverter designs

39. What wire are knurled drive rolls most commonly used on?
Guns
Flux cored wires
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

40. List the factors that determine the mode of metal transfer
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Generally not as accurate

41. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

42. What processes are constant current (CC) power sources designed to be used with?
National Electrical Manufactures Association
Constant voltage (CV)
Guns
SMAW - GTAW

43. What effect does increasing and decreasing the inductance have on the weld?
Constant current (CC)
Penetration and burn - off rate of the electrode
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

44. What does inductance control?
The time rate of response for the current rise and fall
(DCEP) Direct Current Electrode Positive or Reverse polarity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

45. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination
Duty cycle

46. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
If you dont know this check your phone
...
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The resistace to electrical current flow increases with it. Causing the electrode to heat

47. List the three methods of metal transfer with GMAW
Reducing the gas source pressure to a constant working pressure
The time rate of response for the current rise and fall
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer

48. What is the purpose of the shielding gas used in GMAW?
Minimum distortion due to low heat input
Controls the rate of flow of a shielding gas to the gun nozzle
Shielding the molten weld metal from atmospheric contamination
Pressure vessels and the piping industry

49. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The Arc voltage
Constant voltage (CV)
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder

50. What 2 organizations designate specifications for GMAW wires?
The negative side of a welding unit
Constant voltage (CV)
AWS and CSA
The resistace to electrical current flow increases with it. Causing the electrode to heat