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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 an advantage of pulsed arc transfer with GMAW?
The Arc voltage
Penetration and burn - off rate of the electrode
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

2. Why is a fiber washer required and what cylinder gas requires it?
...
Constant current (CC)
To prevent leakage - Carbon Dioxide (CO2)
Motor driven generators - Transformer rectifiers - and Inverter designs

3. What does the abbreviation NEMA stand for?
These terms are quite restrictive and often technically incorrect
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube

4. What happens when the electrode extension is increased?
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow
The resistace to electrical current flow increases with it. Causing the electrode to heat

5. 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
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
Cause flaking - which can clog the liner and contact tube

6. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
15 feet (4.5 meters)
Dry ice can form within the flow control openings and cause blockage of shielding gas
...
To prevent drawing of liquid CO2 (Carbon Dioxide)

7. What is the purpose of the shielding gas used in GMAW?
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

8. What are the 2 types of wire feeders available?
Penetration and burn - off rate of the electrode
Aluminum wire
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination

9. Why is a line heater required when using GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode

10. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns

11. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube
Constant voltage (CV)
The negative side of a welding unit

12. What is a typical flow rate of CO2 for short circuit transfer?
Penetration and burn - off rate of the electrode
...
Guns
5.8 to 12.5 L/min

13. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Gas metal arc welding
Wire feed speed - Voltage control
Duty cycle
The Arc voltage

14. What is another term for electrode holders for GMAW?
SMAW - GTAW
Constant voltage (CV)
Guns
Gives arc voltage values to the control system of the feeder

15. In the GMAW process what does voltage control?
Puddle fluidity
1/4 inch to 1/2 inch
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow

16. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Constant current (CC)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

17. 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
Higher 26 to 35 arc volts
Duty cycle
Shielding the molten weld metal from atmospheric contamination

18. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)

19. What is the key advantage of short circuiting transfer?
AWS and CSA
If you dont know this check your phone
Duty cycle
Minimum distortion due to low heat input

20. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Speed of the feed motor and - starting / stopping electrode feed

21. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
The negative side of a welding unit
Welding process that joins metals by heating them with an electric arc
Generally not as accurate

22. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)
When the filler wire is in direct contract with the base metal

23. Why is globular transfer generally avoided with GMAW?
Generally not as accurate
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)

24. List 3 forms compressed gases may be supplied for welding
Welding process that joins metals by heating them with an electric arc
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW

25. What does the term GMAW identify?
Gives arc voltage values to the control system of the feeder
Gas metal arc welding
1/4 inch to 1/2 inch
Constant- speed wire feeders and Voltage- sennsing wire feeders

26. What controls the wire speed on a voltage sensing wire feeder?
The time rate of response for the current rise and fall
The Arc voltage
Duty cycle
Gives arc voltage values to the control system of the feeder

27. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage
3
Aluminum wire

28. When is the metal transferred with short circuit transfer?
AWS and CSA
Duty cycle
Spatter problems and poor weld appearance
When the filler wire is in direct contract with the base metal

29. What effect does increasing and decreasing the inductance have on the weld?
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)

30. What 2 controls are found on a GMAW set- up?
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced

31. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Aluminum wire
Wire feed speed - Voltage control
Insufficient current to melt the wire off cleanly

32. List the factors that determine the mode of metal transfer
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)

33. List several industries that would use GMAW
Duty cycle
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control

34. What wire are knurled drive rolls most commonly used on?
Speed of the feed motor and - starting / stopping electrode feed
Flux cored wires
Voltage is the force that overcomes resistance to allow amperage flow
DCEP (Direct Current Electrode Positive) Reverse Polarity

35. List 3 wire drive systems and give a short description of each
These terms are quite restrictive and often technically incorrect
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
V groove or U groove

36. List the three methods of metal transfer with GMAW
Aluminum wire
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
85%

37. How are GMAW guns rated?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure

38. What does inductance control?
...
The time rate of response for the current rise and fall
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Reducing the gas source pressure to a constant working pressure

39. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
5.8 to 12.5 L/min
Generally not as accurate
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube

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

41. How many times per second does short circuiting take place?
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
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders

42. Why is the term GMAW preferred over MIG or MAG?
Reducing the gas source pressure to a constant working pressure
These terms are quite restrictive and often technically incorrect
85%
1/4 inch to 1/2 inch

43. What does voltage do in an electrical circuit?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

44. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts
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

45. What would be an indication that the drive roll pressure is adjusted correctly?
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent drawing of liquid CO2 (Carbon Dioxide)

46. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control
Penetration and burn - off rate of the electrode
...

47. With straight polarity where is 2/3 of the arc energy?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The negative side of a welding unit
12 to 22 arc volts
The Arc voltage

48. What is the preferred drive roll design for solid wires?
If you dont know this check your phone
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

49. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Flux cored wires
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders

50. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
By there current carrying capacity
The Arc voltage