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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
Pressure - The rate of flow of a shielding gas
Wire feed speed - Voltage control
DCEP (Direct Current Electrode Positive) Reverse Polarity

2. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure

3. What wire are knurled drive rolls most commonly used on?
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
Flux cored wires

4. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode

5. What effect does increasing and decreasing the inductance have on the weld?
When the filler wire is in direct contract with the base metal
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

6. What is the disadvantage of the gauge preset type of regulator/flowmeter?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect
Generally not as accurate

7. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas

8. What is the recommended electrode stick- out for .035 solid wire?
Spatter problems and poor weld appearance
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant- speed wire feeders and Voltage- sennsing wire feeders

9. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
The Arc voltage
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant- speed wire feeders and Voltage- sennsing wire feeders

10. What is the maximum distance that hard wire can be successfully pushed?
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
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA
15 feet (4.5 meters)

11. What is a typical flow rate of CO2 for short circuit transfer?
...
Wire feed speed - Voltage control
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min

12. 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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced
3

13. With straight polarity where is 2/3 of the arc energy?
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed

14. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Reducing the gas source pressure to a constant working pressure

15. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow

16. In the GMAW process what does amperage control?
3
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode
Flux cored wires

17. What does the term GMAW identify?
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect

18. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle
The negative side of a welding unit

19. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
To limit the short circuiting current so that spatter is reduced
Welding process that joins metals by heating them with an electric arc
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

20. A pull type drive system is usually used on what type of material?
To limit the short circuiting current so that spatter is reduced
The resistace to electrical current flow increases with it. Causing the electrode to heat
Aluminum wire
Welding process that joins metals by heating them with an electric arc

21. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
By there current carrying capacity
SMAW - GTAW
Aluminum wire

22. What is another term for electrode holders for GMAW?
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
Controls the rate of flow of a shielding gas to the gun nozzle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

23. What is the preferred drive roll design for solid wires?
Constant- speed wire feeders and Voltage- sennsing wire feeders
V groove or U groove
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure

24. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gives arc voltage values to the control system of the feeder
Duty cycle
Minimum distortion due to low heat input

25. What happens when the electrode extension is increased?
When the filler wire is in direct contract with the base metal
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant voltage (CV)
If you dont know this check your phone

26. What is the required arc voltage used for short circuit transfer?
85%
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
12 to 22 arc volts
Generally not as accurate

27. What does inductance control?
The time rate of response for the current rise and fall
Generally not as accurate
SMAW - GTAW
When the filler wire is in direct contract with the base metal

28. List the factors that determine the mode of metal transfer
Aluminum wire
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
3

29. What power sources are used with the GMAW Process?
V groove or U groove
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Motor driven generators - Transformer rectifiers - and Inverter designs

30. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
DCEP (Direct Current Electrode Positive) Reverse Polarity
3
20 to 200 times per second
Generally not as accurate

31. What are the 2 types of wire feeders available?
Reducing the gas source pressure to a constant working pressure
Minutes of elapsed time continually run (out of 10 minutes)
Constant- speed wire feeders and Voltage- sennsing wire feeders
By there current carrying capacity

32. List several industries that would use GMAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry

33. What does the abbreviation NEMA stand for?
Constant current (CC)
By there current carrying capacity
If you dont know this check your phone
National Electrical Manufactures Association

34. 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
Gas metal arc welding
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)

35. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
The negative side of a welding unit
Wire feed speed
When the filler wire is in direct contract with the base metal

36. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

37. Give a description of 'pinch effect'
Flux cored wires
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly

38. Why is a line heater required when using GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%

39. List 3 wire drive systems and give a short description of each
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)

40. What processes are constant current (CC) power sources designed to be used with?
Penetration and burn - off rate of the electrode
Gives arc voltage values to the control system of the feeder
SMAW - GTAW
Spatter problems and poor weld appearance

41. What is an advantage of pulsed arc transfer with GMAW?
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To limit the short circuiting current so that spatter is reduced

42. What would be an indication that the drive roll pressure is adjusted correctly?
Cause flaking - which can clog the liner and contact tube
Penetration and burn - off rate of the electrode
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)

43. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
...
Aluminum wire

44. In the GMAW process what does voltage control?
Puddle fluidity
15 feet (4.5 meters)
If you dont know this check your phone
1/4 inch to 1/2 inch

45. What is the main purpose of 'slope'?
Minutes of elapsed time continually run (out of 10 minutes)
To prevent leakage - Carbon Dioxide (CO2)
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced

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

47. List the basic equipment requirements for the GMAW process
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Flux cored wires
Pressure vessels and the piping industry

48. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed
SMAW - GTAW

49. List the three methods of metal transfer with GMAW
Duty cycle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Higher 26 to 35 arc volts

50. List 3 forms compressed gases may be supplied for welding
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze