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 is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Welding process that joins metals by heating them with an electric arc
...
Reducing the gas source pressure to a constant working pressure
If you dont know this check your phone

2. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
National Electrical Manufactures Association

3. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Wire feed speed
Cause flaking - which can clog the liner and contact tube
Generally not as accurate
3

4. Give a description of 'pinch effect'
Higher 26 to 35 arc volts
To prevent leakage - Carbon Dioxide (CO2)
Insufficient current to melt the wire off cleanly
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

5. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Controls the rate of flow of a shielding gas to the gun nozzle
Dry ice can form within the flow control openings and cause blockage of shielding gas
Voltage is the force that overcomes resistance to allow amperage flow

6. What controls amperage when using GMAW?
Wire feed speed
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

7. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow

8. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
V groove or U groove
Flux cored wires
Aluminum wire

9. What is a typical flow rate of CO2 for short circuit transfer?
Wire feed speed
To prevent leakage - Carbon Dioxide (CO2)
Higher 26 to 35 arc volts
5.8 to 12.5 L/min

10. In the GMAW process what does amperage control?
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode
3
Guns

11. A pull type drive system is usually used on what type of material?
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity
Aluminum wire

12. What does the wire feeder control?
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure

13. 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)
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance

14. What is another term for electrode holders for GMAW?
Flux cored wires
Higher 26 to 35 arc volts
Guns
National Electrical Manufactures Association

15. How are GMAW guns rated?
V groove or U groove
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly
By there current carrying capacity

16. What does inductance control?
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
The time rate of response for the current rise and fall

17. What type of power source is commonly used with a voltage sensing wire feeder?
Pressure vessels and the piping industry
To prevent drawing of liquid CO2 (Carbon Dioxide)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)

18. What power sources are used with the GMAW Process?
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs
Guns
AWS and CSA

19. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Pressure vessels and the piping industry

20. A 10 minute cycle of welding time vs cooling time a given machine can handle.
V groove or U groove
Gas metal arc welding
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)

21. 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
Voltage is the force that overcomes resistance to allow amperage flow

22. What does the term GMAW identify?
Gas metal arc welding
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second

23. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat

24. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

25. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
12 to 22 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
3
Wire feeds smoothly (yet will slip should a problem occur in the gun)

26. 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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination
Cause flaking - which can clog the liner and contact tube

27. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination

28. 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
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
V groove or U groove

29. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min
15 feet (4.5 meters)
Generally not as accurate

30. What does a flowmeter do and what does it measure?
3
Higher 26 to 35 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire

31. What processes are constant current (CC) power sources designed to be used with?
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly
SMAW - GTAW
5.8 to 12.5 L/min

32. What 2 organizations designate specifications for GMAW wires?
Duty cycle
AWS and CSA
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal

33. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
The Arc voltage
These terms are quite restrictive and often technically incorrect
Constant voltage (CV)

34. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)

35. List 3 forms compressed gases may be supplied for welding
National Electrical Manufactures Association
The negative side of a welding unit
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

36. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Reducing the gas source pressure to a constant working pressure
Minimum distortion due to low heat input
Short- circuiting transfer - Globular transfer - Spray transfer

37. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
Higher 26 to 35 arc volts

38. Why must CO2 cylinders be used in the vertical position?
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry
Spatter problems and poor weld appearance

39. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
Higher 26 to 35 arc volts

40. Why is globular transfer generally avoided with GMAW?
Gives arc voltage values to the control system of the feeder
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

41. What is the key advantage of short circuiting transfer?
Aluminum wire
Minimum distortion due to low heat input
Spatter problems and poor weld appearance
Controls the rate of flow of a shielding gas to the gun nozzle

42. List several industries that would use GMAW
Pressure vessels and the piping industry
V groove or U groove
If you dont know this check your phone
Flux cored wires

43. List the basic equipment requirements for the GMAW process
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. Why is a fiber washer required and what cylinder gas requires it?
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
DCEP (Direct Current Electrode Positive) Reverse Polarity

45. What output on the welding machine is used to rate the duty cycle?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)
To limit the short circuiting current so that spatter is reduced

46. What is the recommended electrode stick- out for .035 solid wire?
Spatter problems and poor weld appearance
Cause flaking - which can clog the liner and contact tube
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder

47. What is the effect of too much slope?
20 to 200 times per second
The Arc voltage
Puddle fluidity
Insufficient current to melt the wire off cleanly

48. List 3 wire drive systems and give a short description of each
Wire feed speed
Cause flaking - which can clog the liner and contact tube
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

49. 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
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association

50. What would be an indication that the drive roll pressure is adjusted correctly?
Insufficient current to melt the wire off cleanly
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)
To limit the short circuiting current so that spatter is reduced