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 purpose of the pick- up lead on a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
When the filler wire is in direct contract with the base metal
By there current carrying capacity
Gives arc voltage values to the control system of the feeder

2. What is the preferred drive roll design for solid wires?
Cause flaking - which can clog the liner and contact tube
V groove or U groove
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

3. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

4. What effect does increasing and decreasing the inductance have on the weld?
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW
National Electrical Manufactures Association

5. What does the term GMAW identify?
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding
The time rate of response for the current rise and fall
Constant voltage (CV)

6. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire

7. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
DCEP (Direct Current Electrode Positive) Reverse Polarity
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)

8. What is the main purpose of 'slope'?
Wire feed speed - Voltage control
The Arc voltage
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced

9. List the factors that determine the mode of metal transfer
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)
Constant current (CC)

10. How many times per second does short circuiting take place?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or Reverse polarity

11. What is the key advantage of short circuiting transfer?
12 to 22 arc volts
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed
Spatter problems and poor weld appearance

12. What would be an indication that the drive roll pressure is adjusted correctly?
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)

13. In the GMAW process what does voltage control?
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
3
Puddle fluidity

14. With straight polarity where is 2/3 of the arc energy?
Speed of the feed motor and - starting / stopping electrode feed
The negative side of a welding unit
(DCEP) Direct Current Electrode Positive or Reverse polarity
Cause flaking - which can clog the liner and contact tube

15. What is the purpose of a regulator and what does it indicate on its gauges?
To limit the short circuiting current so that spatter is reduced
V groove or U groove
DCEP (Direct Current Electrode Positive) Reverse Polarity
Reducing the gas source pressure to a constant working pressure

16. What wire are knurled drive rolls most commonly used on?
V groove or U groove
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts

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

18. What is the purpose of the shielding gas used in GMAW?
Pressure vessels and the piping industry
Wire feed speed
85%
Shielding the molten weld metal from atmospheric contamination

19. Why is a line heater required when using GMAW?
SMAW - GTAW
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
Pressure - The rate of flow of a shielding gas

20. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
5.8 to 12.5 L/min
12 to 22 arc volts
Generally not as accurate

21. List 3 forms compressed gases may be supplied for welding
Constant current (CC)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect

22. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
V groove or U groove

23. What are the 2 types of wire feeders available?
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Pressure vessels and the piping industry

24. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Voltage is the force that overcomes resistance to allow amperage flow

25. What is a solenoid valve and what actuates it?
Constant current (CC)
Cause flaking - which can clog the liner and contact tube
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

26. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Guns
If you dont know this check your phone
Insufficient current to melt the wire off cleanly
Gives arc voltage values to the control system of the feeder

27. Draw a typical volt amp curve for a machine that is designed for GMAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone

28. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
AWS and CSA

29. What does the wire feeder control?
3
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
The time rate of response for the current rise and fall

30. Why is globular transfer generally avoided with GMAW?
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA
Spatter problems and poor weld appearance

31. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Motor driven generators - Transformer rectifiers - and Inverter designs
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube

32. What does inductance control?
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
AWS and CSA
(DCEP) Direct Current Electrode Positive or Reverse polarity
The time rate of response for the current rise and fall

33. What processes are constant current (CC) power sources designed to be used with?
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
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input

34. What does the abbreviation NEMA stand for?
Speed of the feed motor and - starting / stopping electrode feed
...
Duty cycle
National Electrical Manufactures Association

35. What happens when the electrode extension is increased?
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
The resistace to electrical current flow increases with it. Causing the electrode to heat
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Dry ice can form within the flow control openings and cause blockage of shielding gas

36. Regulators control_____________ flowmeters SHOW____________.
National Electrical Manufactures Association
Wire feed speed
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas

37. What is the disadvantage of the gauge preset type of regulator/flowmeter?
The negative side of a welding unit
Pressure - The rate of flow of a shielding gas
Generally not as accurate
Wire feed speed - Voltage control

38. What controls the wire speed on a voltage sensing wire feeder?
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
V groove or U groove
The Arc voltage

39. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed

40. What is another term for electrode holders for GMAW?
15 feet (4.5 meters)
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer

41. Why must CO2 cylinders be used in the vertical position?
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding

42. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Flux cored wires
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

43. What does a flowmeter do and what does it measure?
15 feet (4.5 meters)
Controls the rate of flow of a shielding gas to the gun nozzle
3
The negative side of a welding unit

44. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Wire feed speed
Constant- speed wire feeders and Voltage- sennsing wire feeders
AWS and CSA
85%

45. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minimum distortion due to low heat input
AWS and CSA

46. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
15 feet (4.5 meters)
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination

47. Why is a fiber washer required and what cylinder gas requires it?
V groove or U groove
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)

48. In the GMAW process what does amperage control?
Flux cored wires
Penetration and burn - off rate of the electrode
The negative side of a welding unit
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

49. What is the effect of too much slope?
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
Puddle fluidity
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat

50. Give a description of 'pinch effect'
These terms are quite restrictive and often technically incorrect
V groove or U groove
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field