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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. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
85%
Wire feed speed - Voltage 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

2. List 3 wire drive systems and give a short description of each
Minutes of elapsed time continually run (out of 10 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
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
3
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity

4. What controls the wire speed on a voltage sensing wire feeder?
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure
The Arc voltage
These terms are quite restrictive and often technically incorrect

5. What is another term for electrode holders for GMAW?
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
Guns

6. List 3 forms compressed gases may be supplied for welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Voltage is the force that overcomes resistance to allow amperage flow

7. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Insufficient current to melt the wire off cleanly

8. Give a description of 'pinch effect'
12 to 22 arc volts
Generally not as accurate
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
DCEP (Direct Current Electrode Positive) Reverse Polarity

9. Draw a typical volt amp curve for a machine that is designed for GMAW
Flux cored wires
Insufficient current to melt the wire off cleanly
Constant voltage (CV)
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10. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association

11. Why is a fiber washer required and what cylinder gas requires it?
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

12. How are GMAW guns rated?
By there current carrying capacity
V groove or U groove
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder

13. In the GMAW process what does amperage control?
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode
Gas metal arc welding

14. What wire are knurled drive rolls most commonly used on?
12 to 22 arc volts
1/4 inch to 1/2 inch
The Arc voltage
Flux cored wires

15. What does the wire feeder control?
Constant voltage (CV)
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow

16. List several industries that would use GMAW
1/4 inch to 1/2 inch
5.8 to 12.5 L/min
Pressure vessels and the piping industry
DCEP (Direct Current Electrode Positive) Reverse Polarity

17. A pull type drive system is usually used on what type of material?
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer

18. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Higher 26 to 35 arc volts
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect

19. What does the term GMAW identify?
85%
National Electrical Manufactures Association
Gas metal arc welding
Guns

20. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

21. What is the preferred drive roll design for solid wires?
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)
V groove or U groove
20 to 200 times per second

22. What output on the welding machine is used to rate the duty cycle?
Welding process that joins metals by heating them with an electric arc
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)
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 power sources are used with the GMAW Process?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow

24. 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)
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal

25. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry

26. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)
...
Penetration and burn - off rate of the electrode

27. With straight polarity where is 2/3 of the arc energy?
To prevent drawing of liquid CO2 (Carbon Dioxide)
The negative side of a welding unit
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Gives arc voltage values to the control system of the feeder

28. What processes are constant current (CC) power sources designed to be used with?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
If you dont know this check your phone
SMAW - GTAW

29. List the basic equipment requirements for the GMAW process
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Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The negative side of a welding unit

30. What does the abbreviation NEMA stand for?
20 to 200 times per second
National Electrical Manufactures Association
Wire feed speed - Voltage control
By there current carrying capacity

31. What does inductance control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow
The time rate of response for the current rise and fall
Flux cored wires

32. In the GMAW process what does voltage control?
Cause flaking - which can clog the liner and contact tube
The time rate of response for the current rise and fall
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity

33. 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
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
Generally not as accurate
Constant current (CC)

34. What 2 controls are found on a GMAW set- up?
When the filler wire is in direct contract with the base metal
Puddle fluidity
Wire feed speed - Voltage control
The time rate of response for the current rise and fall

35. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The Arc voltage

36. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
AWS and CSA

37. What current and polarity is generally used with GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)

38. What type of power source is commonly used with a voltage sensing wire feeder?
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant current (CC)
By there current carrying capacity

39. Regulators control_____________ flowmeters SHOW____________.
Generally not as accurate
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
5.8 to 12.5 L/min

40. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
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
(DCEP) Direct Current Electrode Positive or Reverse polarity
Voltage is the force that overcomes resistance to allow amperage flow

41. What controls amperage when using GMAW?
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube
Wire feed speed
Wire feed speed - Voltage control

42. Why is the term GMAW preferred over MIG or MAG?
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect
Constant current (CC)

43. What does voltage do in an electrical circuit?
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%
Voltage is the force that overcomes resistance to allow amperage flow

44. What is the required arc voltage used for short circuit transfer?
3
...
Constant voltage (CV)
12 to 22 arc volts

45. What is the purpose of a regulator and what does it indicate on its gauges?
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Reducing the gas source pressure to a constant working pressure
AWS and CSA

46. List the factors that determine the mode of metal transfer
Puddle fluidity
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant current (CC)

47. What effect does increasing and decreasing the inductance have on the weld?
3
Generally not as accurate
5.8 to 12.5 L/min
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

48. What are the 2 types of wire feeders available?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
5.8 to 12.5 L/min
Puddle fluidity
Constant- speed wire feeders and Voltage- sennsing wire feeders

49. Why is a line heater required when using GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Shielding the molten weld metal from atmospheric contamination
Dry ice can form within the flow control openings and cause blockage of shielding gas
To prevent leakage - Carbon Dioxide (CO2)

50. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
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
Gives arc voltage values to the control system of the feeder
12 to 22 arc volts