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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
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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 output on the welding machine is used to rate the duty cycle?
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc

2. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
3
Wire feed speed
Cause flaking - which can clog the liner and contact tube

3. What effect does increasing and decreasing the inductance have on the weld?
SMAW - GTAW
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
Cause flaking - which can clog the liner and contact tube

4. How are GMAW guns rated?
By there current carrying capacity
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)
15 feet (4.5 meters)

5. What is a solenoid valve and what actuates it?
...
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The negative side of a welding unit

6. What is the maximum distance that hard wire can be successfully pushed?
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

7. List the basic equipment requirements for the GMAW process
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

8. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
To prevent leakage - Carbon Dioxide (CO2)
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas

9. What power sources are used with the GMAW Process?
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Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc

10. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
These terms are quite restrictive and often technically incorrect
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

11. What 2 controls are found on a GMAW set- up?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
Constant voltage (CV)

12. What is the preferred drive roll design for solid wires?
The resistace to electrical current flow increases with it. Causing the electrode to heat
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove
By there current carrying capacity

13. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Guns
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination

14. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube

15. A pull type drive system is usually used on what type of material?
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second
Aluminum wire
Short- circuiting transfer - Globular transfer - Spray transfer

16. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Generally not as accurate
Duty cycle
Gives arc voltage values to the control system of the feeder
Aluminum wire

17. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Puddle fluidity
Duty cycle
15 feet (4.5 meters)
Gas metal arc welding

18. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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 or Reverse polarity

19. What is the purpose of the shielding gas used in GMAW?
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination

20. List the three methods of metal transfer with GMAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
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
Short- circuiting transfer - Globular transfer - Spray transfer
When the filler wire is in direct contract with the base metal

21. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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Controls the rate of flow of a shielding gas to the gun nozzle
To limit the short circuiting current so that spatter is reduced

22. What is the effect of too much slope?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Insufficient current to melt the wire off cleanly
Aluminum wire
National Electrical Manufactures Association

23. List 3 forms compressed gases may be supplied for welding
...
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

24. In the GMAW process what does voltage control?
Puddle fluidity
Wire feed speed - Voltage control
85%
20 to 200 times per second

25. What does inductance control?
85%
Wire feed speed
The time rate of response for the current rise and fall
...

26. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)

27. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas

28. With straight polarity where is 2/3 of the arc energy?
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

29. Why is globular transfer generally avoided with GMAW?
AWS and CSA
If you dont know this check your phone
Spatter problems and poor weld appearance
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

30. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
AWS and CSA
Higher 26 to 35 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

31. What type of power source is used with a constant speed wire feeder?
Constant current (CC)
12 to 22 arc volts
V groove or U groove
Constant voltage (CV)

32. What does the abbreviation NEMA stand for?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant current (CC)
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association

33. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode

34. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Penetration and burn - off rate of the electrode
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
85%

35. Why is the term GMAW preferred over MIG or MAG?
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect

36. What would be an indication that the drive roll pressure is adjusted correctly?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Flux cored wires
Shielding the molten weld metal from atmospheric contamination
Wire feeds smoothly (yet will slip should a problem occur in the gun)

37. Give a brief description of the GMAW process
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
The time rate of response for the current rise and fall

38. What wire are knurled drive rolls most commonly used on?
Higher 26 to 35 arc volts
...
Flux cored wires
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

39. What controls the wire speed on a voltage sensing wire feeder?
Constant voltage (CV)
AWS and CSA
The Arc voltage
Constant current (CC)

40. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
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
These terms are quite restrictive and often technically incorrect

41. What controls amperage when using GMAW?
Reducing the gas source pressure to a constant working pressure
Higher 26 to 35 arc volts
Wire feed speed
1/4 inch to 1/2 inch

42. What happens when the electrode extension is increased?
Constant voltage (CV)
Pressure vessels and the piping industry
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns

43. What is the key advantage of short circuiting transfer?
Gas metal arc welding
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input

44. What are the 2 types of wire feeders available?
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

45. What is another term for electrode holders for GMAW?
Guns
Short- circuiting transfer - Globular transfer - Spray transfer
85%
12 to 22 arc volts

46. In the GMAW process what does amperage control?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
Aluminum wire
Insufficient current to melt the wire off cleanly

47. Give a description of 'pinch effect'
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer
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

48. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder
Generally not as accurate
Voltage is the force that overcomes resistance to allow amperage flow

49. What current and polarity is generally used with GMAW?
The Arc voltage
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity

50. Regulators control_____________ flowmeters SHOW____________.
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
...