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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.
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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 disadvantage of the gauge preset type of regulator/flowmeter?
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
Pressure - The rate of flow of a shielding gas
Generally not as accurate

2. What is an advantage of pulsed arc transfer with GMAW?
These terms are quite restrictive and often technically incorrect
Short- circuiting transfer - Globular transfer - Spray transfer
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

3. What output on the welding machine is used to rate the duty cycle?
Reducing the gas source pressure to a constant working pressure
Minutes of elapsed time continually run (out of 10 minutes)
Guns
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

4. Give a brief description of the GMAW process
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc

5. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure

6. What is the purpose of a regulator and what does it indicate on its gauges?
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity
Reducing the gas source pressure to a constant working pressure

7. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
Duty cycle

8. How many times per second does short circuiting take place?
When the filler wire is in direct contract with the base metal
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode
20 to 200 times per second

9. List several industries that would use GMAW
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)

10. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
...
1/4 inch to 1/2 inch
The negative side of a welding unit

11. A pull type drive system is usually used on what type of material?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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
Reducing the gas source pressure to a constant working pressure
Aluminum wire

12. Why is a line heater required when using GMAW?
SMAW - GTAW
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association

13. Why is a fiber washer required and what cylinder gas requires it?
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
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

14. What is a typical flow rate of CO2 for short circuit transfer?
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
12 to 22 arc volts

15. What is the preferred drive roll design for solid wires?
V groove or U groove
Guns
Spatter problems and poor weld appearance
To prevent drawing of liquid CO2 (Carbon Dioxide)

16. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
20 to 200 times per second
Gives arc voltage values to the control system of the feeder
By there current carrying capacity

17. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant voltage (CV)
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas

18. How are GMAW guns rated?
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

20. What does inductance control?
When the filler wire is in direct contract with the base metal
The time rate of response for the current rise and fall
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination

21. When is the metal transferred with short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
When the filler wire is in direct contract with the base metal
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

22. What does the term GMAW identify?
If you dont know this check your phone
Gas metal arc welding
85%
Reducing the gas source pressure to a constant working pressure

23. What does the abbreviation NEMA stand for?
Pressure vessels and the piping industry
Puddle fluidity
Higher 26 to 35 arc volts
National Electrical Manufactures Association

24. What is another term for electrode holders for GMAW?
Shielding the molten weld metal from atmospheric contamination
Guns
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA

25. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Minimum distortion due to low heat input
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

26. What processes are constant current (CC) power sources designed to be used with?
To limit the short circuiting current so that spatter is reduced
Welding process that joins metals by heating them with an electric arc
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW

27. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone

28. What is the main purpose of 'slope'?
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
To limit the short circuiting current so that spatter is reduced
Duty cycle
Minimum distortion due to low heat input

29. What type of power source is commonly used with a voltage sensing wire feeder?
The negative side of a welding unit
Constant current (CC)
Flux cored wires
Speed of the feed motor and - starting / stopping electrode feed

30. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity
Insufficient current to melt the wire off cleanly

31. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)

32. What current and polarity is generally used with GMAW?
85%
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)

33. List the factors that determine the mode of metal transfer
Shielding the molten weld metal from atmospheric contamination
3
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA

34. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder

35. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association
The time rate of response for the current rise and fall

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant current (CC)
85%
The resistace to electrical current flow increases with it. Causing the electrode to heat
When the filler wire is in direct contract with the base metal

37. In the GMAW process what does voltage control?
Gas metal arc welding
Puddle fluidity
AWS and CSA
When the filler wire is in direct contract with the base metal

38. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance

39. What would be an indication that the drive roll pressure is adjusted correctly?
Gives arc voltage values to the control system of the feeder
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent leakage - Carbon Dioxide (CO2)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

40. List 3 wire drive systems and give a short description of each
1/4 inch to 1/2 inch
Flux cored wires
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

41. What is the maximum distance that hard wire can be successfully pushed?
Wire feed speed
15 feet (4.5 meters)
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow

42. What controls amperage when using GMAW?
Reducing the gas source pressure to a constant working pressure
20 to 200 times per second
Wire feed speed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

43. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode

44. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Pressure - The rate of flow of a shielding gas
Duty cycle
The Arc voltage
To limit the short circuiting current so that spatter is reduced

45. Give a description of 'pinch effect'
Constant current (CC)
When the filler wire is in direct contract with the base metal
By there current carrying capacity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

46. What does the wire feeder control?
Welding process that joins metals by heating them with an electric arc
When the filler wire is in direct contract with the base metal
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

47. What type of power source is used with a constant speed wire feeder?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant voltage (CV)
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)

48. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
20 to 200 times per second
Welding process that joins metals by heating them with an electric arc
85%

49. What effect does increasing and decreasing the inductance have on the weld?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Constant- speed wire feeders and Voltage- sennsing wire feeders
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

50. List the basic equipment requirements for the GMAW process
Voltage is the force that overcomes resistance to allow amperage flow
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground