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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 is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
The time rate of response for the current rise and fall
15 feet (4.5 meters)
Pressure vessels and the piping industry

2. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Insufficient current to melt the wire off cleanly
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. When is the metal transferred with short circuit transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc

4. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Generally not as accurate
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

5. Draw a typical volt amp curve for a machine that is designed for GMAW
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Speed of the feed motor and - starting / stopping electrode feed
...
Constant- speed wire feeders and Voltage- sennsing wire feeders

6. What is a solenoid valve and what actuates it?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

7. What does the term GMAW identify?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer
...

8. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed
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9. List several industries that would use GMAW
AWS and CSA
Shielding the molten weld metal from atmospheric contamination
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry

10. What is the maximum distance that hard wire can be successfully pushed?
Generally not as accurate
15 feet (4.5 meters)
3
Speed of the feed motor and - starting / stopping electrode feed

11. What does voltage do in an electrical circuit?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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
Voltage is the force that overcomes resistance to allow amperage flow

12. What is a typical flow rate of CO2 for short circuit transfer?
Generally not as accurate
5.8 to 12.5 L/min
15 feet (4.5 meters)
AWS and CSA

13. What does inductance control?
The time rate of response for the current rise and fall
Flux cored wires
The Arc voltage
Reducing the gas source pressure to a constant working pressure

14. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed

15. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
Constant current (CC)
Gives arc voltage values to the control system of the feeder

16. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
1/4 inch to 1/2 inch
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
Cause flaking - which can clog the liner and contact tube

17. 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
...
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

18. What would be an indication that the drive roll pressure is adjusted correctly?
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...
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)

19. What output on the welding machine is used to rate the duty cycle?
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

20. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
Duty cycle
Pressure vessels and the piping industry

21. What processes are constant current (CC) power sources designed to be used with?
Duty cycle
SMAW - GTAW
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

22. What type of power source is commonly used with a voltage sensing wire feeder?
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant current (CC)

23. With straight polarity where is 2/3 of the arc energy?
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By there current carrying capacity
The negative side of a welding unit
Aluminum wire

24. What current and polarity is generally used with GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
20 to 200 times per second

25. What effect does increasing and decreasing the inductance have on the weld?
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
5.8 to 12.5 L/min
Cause flaking - which can clog the liner and contact tube

26. List 3 forms compressed gases may be supplied for welding
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)

27. List the factors that determine the mode of metal transfer
The time rate of response for the current rise and fall
Pressure vessels and the piping industry
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
5.8 to 12.5 L/min

28. What wire are knurled drive rolls most commonly used on?
Guns
...
(DCEP) Direct Current Electrode Positive or Reverse polarity
Flux cored wires

29. Give a description of 'pinch effect'
To limit the short circuiting current so that spatter is reduced
If you dont know this check your phone
3
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

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

31. What is an advantage of pulsed arc transfer with GMAW?
3
85%
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To limit the short circuiting current so that spatter is reduced

32. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Penetration and burn - off rate of the electrode
Gas metal arc welding
Generally not as accurate
Minimum distortion due to low heat input

33. Why must CO2 cylinders be used in the vertical position?
The negative side of a welding unit
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 - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)

34. How are GMAW guns rated?
By there current carrying capacity
The time rate of response for the current rise and fall
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination

35. Why is globular transfer generally avoided with GMAW?
V groove or U groove
...
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance

36. What is the recommended electrode stick- out for .035 solid wire?
20 to 200 times per second
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube

37. What happens when the electrode extension is increased?
85%
The resistace to electrical current flow increases with it. Causing the electrode to heat
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity

38. What is the purpose of the shielding gas used in GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination

39. What is the purpose of a regulator and what does it indicate on its gauges?
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
Reducing the gas source pressure to a constant working pressure

40. Why is a fiber washer required and what cylinder gas requires it?
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
Wire feeds smoothly (yet will slip should a problem occur in the gun)

41. What does the wire feeder control?
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed

42. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW
...
If you dont know this check your phone

43. What is the preferred drive roll design for solid wires?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone
AWS and CSA
V groove or U groove

44. List the basic equipment requirements for the GMAW process
85%
3
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

45. What are the 2 types of wire feeders available?
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders

46. What controls the wire speed on a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
The negative side of a welding unit
Insufficient current to melt the wire off cleanly
The Arc voltage

47. In the GMAW process what does voltage control?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant voltage (CV)
Puddle fluidity
12 to 22 arc volts

48. What type of power source is used with a constant speed wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gas metal arc welding
Constant voltage (CV)
If you dont know this check your phone

49. What 2 organizations designate specifications for GMAW wires?
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gas metal arc welding
AWS and CSA

50. Regulators control_____________ flowmeters SHOW____________.
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
The negative side of a welding unit
...