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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. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
3
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Duty cycle

2. 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
Spatter problems and poor weld appearance
Generally not as accurate
...

3. What does the wire feeder control?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
These terms are quite restrictive and often technically incorrect

4. What are the 2 types of wire feeders available?
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

5. List the basic equipment requirements for the GMAW process
Controls the rate of flow of a shielding gas to the gun nozzle
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Higher 26 to 35 arc volts
...

6. What does inductance control?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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
Pressure vessels and the piping industry

7. What is the purpose of a regulator and what does it indicate on its gauges?
Higher 26 to 35 arc volts
3
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure

8. In the GMAW process what does 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
Puddle fluidity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity

9. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders

10. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed
Flux cored wires
15 feet (4.5 meters)

11. What 2 organizations designate specifications for GMAW wires?
If you dont know this check your phone
AWS and CSA
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed

12. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect

13. What does a flowmeter do and what does it measure?
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle

14. When is the metal transferred with short circuit transfer?
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
Short- circuiting transfer - Globular transfer - Spray transfer
When the filler wire is in direct contract with the base metal

15. What happens when the electrode extension is increased?
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat
Duty cycle
Constant current (CC)

16. With straight polarity where is 2/3 of the arc energy?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit

17. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
15 feet (4.5 meters)
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

18. What is the preferred drive roll design for solid wires?
If you dont know this check your phone
V groove or U groove
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%

20. What type of power source is used with a constant speed wire feeder?
15 feet (4.5 meters)
Constant voltage (CV)
20 to 200 times per second
Gives arc voltage values to the control system of the feeder

21. How are GMAW guns rated?
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

22. Regulators control_____________ flowmeters SHOW____________.
To prevent leakage - Carbon Dioxide (CO2)
Pressure - The rate of flow of a shielding gas
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode

23. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Gas metal arc welding
20 to 200 times per second
V groove or U groove

24. What wire are knurled drive rolls most commonly used on?
Minimum distortion due to low heat input
When the filler wire is in direct contract with the base metal
15 feet (4.5 meters)
Flux cored wires

25. List the three methods of metal transfer with GMAW
Penetration and burn - off rate of the electrode
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer

26. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

27. What does the abbreviation NEMA stand for?
20 to 200 times per second
Guns
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode

28. What power sources are used with the GMAW Process?
5.8 to 12.5 L/min
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode

29. List 3 wire drive systems and give a short description of each
National Electrical Manufactures Association
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
3
20 to 200 times per second

30. What is an advantage of pulsed arc transfer with GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gives arc voltage values to the control system of the feeder

31. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts
Puddle fluidity
Pressure vessels and the piping industry

32. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
Shielding the molten weld metal from atmospheric contamination

33. Give a description of 'pinch effect'
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
Short- circuiting transfer - Globular transfer - Spray transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

34. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant current (CC)
Generally not as accurate
Aluminum wire
Gas metal arc welding

35. What is a typical flow rate of CO2 for short circuit transfer?
Constant voltage (CV)
Wire feed speed
5.8 to 12.5 L/min
20 to 200 times per second

36. What effect does increasing and decreasing the inductance have on the weld?
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
15 feet (4.5 meters)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

37. List the factors that determine the mode of metal transfer
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
5.8 to 12.5 L/min
The negative side of a welding unit

38. Why must CO2 cylinders be used in the vertical position?
Gives arc voltage values to the control system of the feeder
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone

39. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
SMAW - GTAW
Duty cycle
If you dont know this check your phone

40. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
Aluminum wire
3

41. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Flux cored wires
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle

42. List several industries that would use GMAW
SMAW - GTAW
Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure vessels and the piping industry

43. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Guns
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gives arc voltage values to the control system of the feeder

44. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

45. What is the main purpose of 'slope'?
The negative side of a welding unit
The Arc voltage
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas

46. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
...
Higher 26 to 35 arc volts
Flux cored wires

47. What current and polarity is generally used with GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding process that joins metals by heating them with an electric arc

48. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
AWS and CSA

49. 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)
Aluminum wire
Shielding the molten weld metal from atmospheric contamination
Motor driven generators - Transformer rectifiers - and Inverter designs

50. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
12 to 22 arc volts