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. 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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry
The Arc voltage

2. 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
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly
If you dont know this check your phone

3. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
...
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The Arc voltage
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed - Voltage control
Gives arc voltage values to the control system of the feeder

5. Give a brief description of the GMAW process
Duty cycle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
Welding process that joins metals by heating them with an electric arc

6. What is a solenoid valve and what actuates it?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Guns

7. A pull type drive system is usually used on what type of material?
Aluminum wire
1/4 inch to 1/2 inch
3
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

8. What is the preferred drive roll design for solid wires?
V groove or U groove
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
85%

9. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
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
Constant voltage (CV)

10. Regulators control_____________ flowmeters SHOW____________.
Controls the rate of flow of a shielding gas to the gun nozzle
Penetration and burn - off rate of the electrode
Pressure - The rate of flow of a shielding gas
Flux cored wires

11. What 2 controls are found on a GMAW set- up?
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Wire feed speed - Voltage control

12. 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
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode
National Electrical Manufactures Association

13. What 2 organizations designate specifications for GMAW wires?
Minimum distortion due to low heat input
These terms are quite restrictive and often technically incorrect
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA

14. What is a typical flow rate of CO2 for short circuit transfer?
If you dont know this check your phone
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min

15. What happens when the electrode extension is increased?
Gas metal arc welding
The resistace to electrical current flow increases with it. Causing the electrode to heat
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts

16. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
85%
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)

17. What current and polarity is generally used with GMAW?
20 to 200 times per second
Constant current (CC)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs

18. Why is a fiber washer required and what cylinder gas requires it?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW
15 feet (4.5 meters)

19. List several industries that would use GMAW
Pressure vessels and the piping industry
V groove or U groove
Cause flaking - which can clog the liner and contact tube
Constant current (CC)

20. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
By there current carrying capacity
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced

21. What type of power source is commonly used with a voltage sensing wire feeder?
12 to 22 arc volts
Constant current (CC)
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc

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

23. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
The time rate of response for the current rise and fall
Puddle fluidity

24. What does a flowmeter do and what does it measure?
The resistace to electrical current flow increases with it. Causing the electrode to heat
The time rate of response for the current rise and fall
Flux cored wires
Controls the rate of flow of a shielding gas to the gun nozzle

25. What power sources are used with the GMAW Process?
1/4 inch to 1/2 inch
3
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs

26. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly
DCEP (Direct Current Electrode Positive) Reverse Polarity
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

27. Why is a line heater required when using GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gas metal arc welding

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
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input

29. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
If you dont know this check your phone
85%

30. 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
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
Insufficient current to melt the wire off cleanly

31. What does the abbreviation NEMA stand for?
Higher 26 to 35 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs

32. With straight polarity where is 2/3 of the arc energy?
Reducing the gas source pressure to a constant working pressure
Flux cored wires
The negative side of a welding unit
Spatter problems and poor weld appearance

33. What does the term GMAW identify?
Gas metal arc welding
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity
SMAW - GTAW

34. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
(DCEP) Direct Current Electrode Positive or Reverse polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Duty cycle

35. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding
SMAW - GTAW
Puddle fluidity

36. List the three methods of metal transfer with GMAW
Cause flaking - which can clog the liner and contact tube
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent leakage - Carbon Dioxide (CO2)
Puddle fluidity

37. What is an advantage of pulsed arc transfer with GMAW?
85%
V groove or U groove
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall

38. Give a description of 'pinch effect'
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

39. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts

40. What does inductance control?
Guns
15 feet (4.5 meters)
The time rate of response for the current rise and fall
By there current carrying capacity

41. In the GMAW process what does voltage control?
Gives arc voltage values to the control system of the feeder
Penetration and burn - off rate of the electrode
Short- circuiting transfer - Globular transfer - Spray transfer
Puddle fluidity

42. What is another term for electrode holders for GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Guns
Aluminum wire
Wire feed speed

43. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Aluminum wire
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. List the factors that determine the mode of metal transfer
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow

45. A 10 minute cycle of welding time vs cooling time a given machine can handle.
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch
Duty cycle
Spatter problems and poor weld appearance

46. List the basic equipment requirements for the GMAW process
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)
Duty cycle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

47. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Puddle fluidity
Flux cored wires
Pressure - The rate of flow of a shielding gas

48. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Aluminum wire
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle

49. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
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

50. What effect does increasing and decreasing the inductance have on the weld?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of 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
Short- circuiting transfer - Globular transfer - Spray transfer