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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. How are GMAW guns rated?
Aluminum wire
If you dont know this check your phone
15 feet (4.5 meters)
By there current carrying capacity

2. What is another term for electrode holders for GMAW?
Constant voltage (CV)
The Arc voltage
Cause flaking - which can clog the liner and contact tube
Guns

3. What is the maximum distance that hard wire can be successfully pushed?
Minimum distortion due to low heat input
15 feet (4.5 meters)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow

4. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
If you dont know this check your phone
By there current carrying capacity
Gives arc voltage values to the control system of the feeder

5. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch

6. What is the required arc voltage used for short circuit transfer?
National Electrical Manufactures Association
Pressure vessels and the piping industry
12 to 22 arc volts
The time rate of response for the current rise and fall

7. When is the metal transferred with short circuit transfer?
1/4 inch to 1/2 inch
By there current carrying capacity
When the filler wire is in direct contract with the base metal
Motor driven generators - Transformer rectifiers - and Inverter designs

8. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Gas metal arc welding
85%
Constant voltage (CV)
Minimum distortion due to low heat input

9. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Dry ice can form within the flow control openings and cause blockage of shielding gas
Guns
Constant current (CC)

10. List 3 wire drive systems and give a short description of each
Dry ice can form within the flow control openings and cause blockage of shielding gas
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
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow

11. How many times per second does short circuiting take place?
Guns
National Electrical Manufactures Association
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second

12. What does the wire feeder control?
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
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

13. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Minutes of elapsed time continually run (out of 10 minutes)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs
3

14. What happens when the electrode extension is increased?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
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15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts

16. 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
3
By there current carrying capacity
SMAW - GTAW

17. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Spatter problems and poor weld appearance
Higher 26 to 35 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders

18. What output on the welding machine is used to rate the duty cycle?
Flux cored wires
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
By there current carrying capacity

19. What would be an indication that the drive roll pressure is adjusted correctly?
SMAW - GTAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle

20. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Aluminum wire
Wire feed speed
Cause flaking - which can clog the liner and contact tube
SMAW - GTAW

21. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Minimum distortion due to low heat input
AWS and CSA
Higher 26 to 35 arc volts

22. Why is the term GMAW preferred over MIG or MAG?
Constant voltage (CV)
1/4 inch to 1/2 inch
Aluminum wire
These terms are quite restrictive and often technically incorrect

23. What wire are knurled drive rolls most commonly used on?
Speed of the feed motor and - starting / stopping electrode feed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA
Flux cored wires

24. 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
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat

25. Give a description of 'pinch effect'
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

26. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
V groove or U groove
Guns

27. What 2 organizations designate specifications for GMAW wires?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)
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

28. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The time rate of response for the current rise and fall

29. In the GMAW process what does voltage control?
Duty cycle
...
Puddle fluidity
5.8 to 12.5 L/min

30. What 2 controls are found on a GMAW set- up?
Generally not as accurate
Dry ice can form within the flow control openings and cause blockage of shielding gas
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control

31. What controls amperage when using GMAW?
85%
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone
Wire feed speed

32. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Motor driven generators - Transformer rectifiers - and Inverter designs
When the filler wire is in direct contract with the base metal
Higher 26 to 35 arc volts

33. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minimum distortion due to low heat input
If you dont know this check your phone

34. List the basic equipment requirements for the GMAW process
V groove or U groove
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%

35. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer

36. List several industries that would use GMAW
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Wire feed speed - Voltage control

37. A pull type drive system is usually used on what type of material?
Pressure vessels and the piping industry
The negative side of a welding unit
National Electrical Manufactures Association
Aluminum wire

38. What is a typical flow rate of CO2 for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly

39. What is the key advantage of short circuiting transfer?
Wire feed speed - Voltage control
Wire feed speed
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input

40. List the three methods of metal transfer with GMAW
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
Constant current (CC)
Pressure vessels and the piping industry

41. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove

42. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
To prevent leakage - Carbon Dioxide (CO2)
AWS and CSA
3

43. What is the recommended electrode stick- out for .035 solid wire?
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts
1/4 inch to 1/2 inch
Wire feed speed - Voltage control

44. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance
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

45. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
12 to 22 arc volts
...
V groove or U groove
15 feet (4.5 meters)

46. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
Guns
5.8 to 12.5 L/min

47. What does inductance control?
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall

48. What controls the wire speed on a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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

49. What is the main purpose of 'slope'?
Duty cycle
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced
V groove or U groove

50. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate