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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 is an advantage of pulsed arc transfer with GMAW?
National Electrical Manufactures Association
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
When the filler wire is in direct contract with the base metal

2. What happens when the electrode extension is increased?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat

3. 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
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
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

4. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
1/4 inch to 1/2 inch

5. What type of power source is commonly used with a voltage sensing wire feeder?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Penetration and burn - off rate of the electrode
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

6. What is the preferred drive roll design for solid wires?
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
Generally not as accurate
If you dont know this check your phone

7. What is the purpose of the shielding gas used in GMAW?
Speed of the feed motor and - starting / stopping electrode feed
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
Controls the rate of flow of a shielding gas to the gun nozzle

8. Why is a line heater required when using GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas

9. A 10 minute cycle of welding time vs cooling time a given machine can handle.
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs

10. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Guns
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders

11. What would be an indication that the drive roll pressure is adjusted correctly?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a shielding gas

12. In the GMAW process what does voltage control?
Guns
Puddle fluidity
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

13. What does the term GMAW identify?
...
Gas metal arc welding
When the filler wire is in direct contract with the base metal
(DCEP) Direct Current Electrode Positive or Reverse polarity

14. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts

15. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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
Gives arc voltage values to the control system of the feeder

16. What is the main purpose of 'slope'?
Higher 26 to 35 arc volts
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced

17. List several industries that would use GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure vessels and the piping industry
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)

18. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
When the filler wire is in direct contract with the base metal
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Puddle fluidity

19. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
...
If you dont know this check your phone

20. With straight polarity where is 2/3 of the arc energy?
AWS and CSA
The Arc voltage
The negative side of a welding unit
Reducing the gas source pressure to a constant working pressure

21. What 2 organizations designate specifications for GMAW wires?
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
SMAW - GTAW
AWS and CSA

22. What power sources are used with the GMAW Process?
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal

23. Why is globular transfer generally avoided with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Spatter problems and poor weld appearance
20 to 200 times per second

24. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity
The time rate of response for the current rise and fall

25. What does voltage do in an electrical circuit?
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)
Voltage is the force that overcomes resistance to allow amperage flow
85%

26. 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
Wire feed speed
When the filler wire is in direct contract with the base metal
...

27. What is the required arc voltage used for short circuit transfer?
Flux cored wires
12 to 22 arc volts
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders

28. What is another term for electrode holders for GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Guns
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)

29. What 2 controls are found on a GMAW set- up?
Aluminum wire
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

30. How many times per second does short circuiting take place?
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

31. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure
5.8 to 12.5 L/min
Duty cycle

32. A pull type drive system is usually used on what type of material?
Wire feed speed - Voltage control
5.8 to 12.5 L/min
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs

33. What effect does increasing and decreasing the inductance have on the weld?
These terms are quite restrictive and often technically incorrect
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly

34. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Aluminum wire
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)

35. Draw a typical volt amp curve for a machine that is designed for GMAW
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone

36. 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
85%
The time rate of response for the current rise and fall
Puddle fluidity

37. Give a brief description of the GMAW process
Generally not as accurate
85%
Welding process that joins metals by heating them with an electric arc
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

38. What are the 2 types of wire feeders available?
85%
(DCEP) Direct Current Electrode Positive or Reverse polarity
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders

39. What does inductance control?
Gas metal arc welding
Wire feed speed
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

40. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
V groove or U groove
The Arc voltage
Reducing the gas source pressure to a constant working pressure
3

41. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced
Short- circuiting transfer - Globular transfer - Spray transfer

42. Why is the term GMAW preferred over MIG or MAG?
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min
The Arc voltage

43. What does a flowmeter do and what does it measure?
If you dont know this check your phone
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
Controls the rate of flow of a shielding gas to the gun nozzle
The negative side of a welding unit

44. What does the abbreviation NEMA stand for?
Wire feed speed - Voltage control
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association
Puddle fluidity

45. What output on the welding machine is used to rate the duty cycle?
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry

46. When is the metal transferred with short circuit transfer?
Gas metal arc welding
When the filler wire is in direct contract with the base metal
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

47. What is the recommended electrode stick- out for .035 solid wire?
85%
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced
Constant current (CC)

48. List 3 wire drive systems and give a short description of each
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
1/4 inch to 1/2 inch
5.8 to 12.5 L/min

49. How are GMAW guns rated?
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
Constant- speed wire feeders and Voltage- sennsing wire feeders
By there current carrying capacity

50. What current and polarity is generally used with GMAW?
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity
20 to 200 times per second
The negative side of a welding unit