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. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Minimum distortion due to low heat input
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders

2. What is the recommended electrode stick- out for .035 solid wire?
National Electrical Manufactures Association
SMAW - GTAW
1/4 inch to 1/2 inch
15 feet (4.5 meters)

3. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Flux cored wires
Insufficient current to melt the wire off cleanly
If you dont know this check your phone

4. What controls amperage when using GMAW?
These terms are quite restrictive and often technically incorrect
Wire feed speed
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts

5. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
The time rate of response for the current rise and fall

6. Why must CO2 cylinders be used in the vertical position?
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity
Reducing the gas source pressure to a constant working pressure

7. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Wire feed speed
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders

8. Why is a line heater required when using GMAW?
Penetration and burn - off rate of the electrode
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall

9. 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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)

10. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone
National Electrical Manufactures Association

11. What is another term for electrode holders for GMAW?
3
Constant- speed wire feeders and Voltage- sennsing wire feeders
To limit the short circuiting current so that spatter is reduced
Guns

12. What controls the wire speed on a voltage sensing wire feeder?
Spatter problems and poor weld appearance
Shielding the molten weld metal from atmospheric contamination
The Arc voltage
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

13. What is the effect of too much slope?
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs

14. Why is the term GMAW preferred over MIG or MAG?
Wire feed speed
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect

15. How many times per second does short circuiting take place?
When the filler wire is in direct contract with the base metal
20 to 200 times per second
Minimum distortion due to low heat input
The negative side of a welding unit

16. 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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Motor driven generators - Transformer rectifiers - and Inverter designs

17. What does the abbreviation NEMA stand for?
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association

18. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
National Electrical Manufactures Association

19. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
By there current carrying capacity
Duty cycle
Guns

20. What does the term GMAW identify?
Wire feed speed - Voltage control
National Electrical Manufactures Association
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer

21. Regulators control_____________ flowmeters SHOW____________.
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced

22. What is the key advantage of short circuiting transfer?
Generally not as accurate
Minimum distortion due to low heat input
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity

23. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone

24. What wire are knurled drive rolls most commonly used on?
SMAW - GTAW
Higher 26 to 35 arc volts
The Arc voltage
Flux cored wires

25. List the three methods of metal transfer with GMAW
Pressure - The rate of flow of a shielding gas
Guns
Short- circuiting transfer - Globular transfer - Spray transfer
Shielding the molten weld metal from atmospheric contamination

26. What happens when the electrode extension is increased?
Welding process that joins metals by heating them with an electric arc
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent drawing of liquid CO2 (Carbon Dioxide)
Generally not as accurate

27. List the factors that determine the mode of metal transfer
Wire feed speed
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

28. A 10 minute cycle of welding time vs cooling time a given machine can handle.
The time rate of response for the current rise and fall
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat

29. List the basic equipment requirements for the GMAW process
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant voltage (CV)
The time rate of response for the current rise and fall
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

30. What is the required arc voltage used for short circuit transfer?
Guns
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

31. What output on the welding machine is used to rate the duty cycle?
If you dont know this check your phone
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)
To prevent leakage - Carbon Dioxide (CO2)

32. Draw a typical volt amp curve for a machine that is designed for GMAW
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone

33. In the GMAW process what does voltage control?
Puddle fluidity
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow
Short- circuiting transfer - Globular transfer - Spray transfer

34. When is the metal transferred with short circuit transfer?
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
When the filler wire is in direct contract with the base metal

35. In the GMAW process what does amperage control?
The Arc voltage
Reducing the gas source pressure to a constant working pressure
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control

36. Why is a fiber washer required and what cylinder gas requires it?
Insufficient current to melt the wire off cleanly
Constant voltage (CV)
If you dont know this check your phone
To prevent leakage - Carbon Dioxide (CO2)

37. What effect does increasing and decreasing the inductance have on the weld?
Pressure - The rate of flow of a shielding gas
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
Wire feed speed - Voltage control

38. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Wire feed speed
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity

39. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ 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
When the filler wire is in direct contract with the base metal
3
Pressure vessels and the piping industry

40. How are GMAW guns rated?
By there current carrying capacity
12 to 22 arc volts
...
Minimum distortion due to low heat input

41. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
V groove or U groove
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Constant current (CC)

42. What is the purpose of the shielding gas used in GMAW?
The negative side of a welding unit
Gas metal arc welding
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination

43. What does inductance control?
85%
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity

44. What is the disadvantage of the gauge preset type of regulator/flowmeter?
20 to 200 times per second
Dry ice can form within the flow control openings and cause blockage of shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
Generally not as accurate

45. What does voltage do in an electrical circuit?
...
To prevent drawing of liquid CO2 (Carbon Dioxide)
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone

46. What type of power source is commonly used with a voltage sensing wire feeder?
If you dont know this check your phone
The negative side of a welding unit
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer

47. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
To prevent drawing of liquid CO2 (Carbon Dioxide)
To limit the short circuiting current so that spatter is reduced
Motor driven generators - Transformer rectifiers - and Inverter designs
...

48. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

49. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
SMAW - GTAW

50. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
5.8 to 12.5 L/min
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld