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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 many times per second does short circuiting take place?
Gives arc voltage values to the control system of the feeder
20 to 200 times per second
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Reducing the gas source pressure to a constant working pressure

2. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)

3. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
1/4 inch to 1/2 inch
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

4. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. What effect does increasing and decreasing the inductance have on the weld?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
(DCEP) Direct Current Electrode Positive or Reverse polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gas metal arc welding

6. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Minimum distortion due to low heat input
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect

7. What is the required arc voltage used for short circuit transfer?
Reducing the gas source pressure to a constant working pressure
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts

8. What is a solenoid valve and what actuates it?
1/4 inch to 1/2 inch
SMAW - GTAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

9. How are GMAW guns rated?
Short- circuiting transfer - Globular transfer - Spray transfer
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect
By there current carrying capacity

10. List several industries that would use GMAW
3
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry

11. Regulators control_____________ flowmeters SHOW____________.
Puddle fluidity
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone

12. What is the purpose of a regulator and what does it indicate on its gauges?
When the filler wire is in direct contract with the base metal
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
Constant current (CC)

13. In the GMAW process what does voltage control?
The time rate of response for the current rise and fall
The Arc voltage
Puddle fluidity
Minutes of elapsed time continually run (out of 10 minutes)

14. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed - Voltage control
...
AWS and CSA

15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Duty cycle
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
3

16. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)

17. Why must CO2 cylinders be used in the vertical position?
Constant voltage (CV)
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
To prevent drawing of liquid CO2 (Carbon Dioxide)

18. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
V groove or U groove

19. What happens when the electrode extension is increased?
The Arc voltage
(DCEP) Direct Current Electrode Positive or Reverse polarity
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

20. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input
Higher 26 to 35 arc volts

21. What is another term for electrode holders for GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Guns
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. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Guns
The time rate of response for the current rise and fall
3

23. What 2 controls are found on a GMAW set- up?
Motor driven generators - Transformer rectifiers - and Inverter designs
3
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas

24. What does voltage do in an electrical circuit?
Speed of the feed motor and - starting / stopping electrode feed
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)

25. What current and polarity is generally used with GMAW?
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders

26. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Gas metal arc welding
12 to 22 arc volts
If you dont know this check your phone
Pressure vessels and the piping industry

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

28. What output on the welding machine is used to rate the duty cycle?
If you dont know this check your phone
Speed of the feed motor and - starting / stopping electrode feed
Guns
Minutes of elapsed time continually run (out of 10 minutes)

29. List 3 wire drive systems and give a short description of each
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minimum distortion due to low heat input
Puddle fluidity
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

30. Give a brief description of the GMAW process
By there current carrying capacity
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc
These terms are quite restrictive and often technically incorrect

31. What is the preferred drive roll design for solid wires?
V groove or U groove
To prevent leakage - Carbon Dioxide (CO2)
3
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

32. When is the metal transferred with short circuit transfer?
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
When the filler wire is in direct contract with the base metal

33. Why is globular transfer generally avoided with GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Spatter problems and poor weld appearance

34. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

35. What are the 2 types of wire feeders available?
The negative side of a welding unit
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding process that joins metals by heating them with an electric arc
Constant- speed wire feeders and Voltage- sennsing wire feeders

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
20 to 200 times per second
Wire feed speed
85%
Cause flaking - which can clog the liner and contact tube

37. List the three methods of metal transfer with GMAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer
Aluminum wire

38. What is an advantage of pulsed arc transfer with GMAW?
Minimum distortion due to low heat input
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
...

39. What type of power source is used with a constant speed wire feeder?
3
5.8 to 12.5 L/min
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure

40. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
Aluminum wire
12 to 22 arc volts
Reducing the gas source pressure to a constant working pressure

41. List the basic equipment requirements for the GMAW process
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage
Pressure vessels and the piping industry

42. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The time rate of response for the current rise and fall
Insufficient current to melt the wire off cleanly

43. What is the key advantage of short circuiting transfer?
Minutes of elapsed time continually run (out of 10 minutes)
Minimum distortion due to low heat input
Constant current (CC)
Aluminum wire

44. What controls amperage when using GMAW?
By there current carrying capacity
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc
Wire feed speed

45. List 3 forms compressed gases may be supplied for welding
Minutes of elapsed time continually run (out of 10 minutes)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

46. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube

47. Why is a line heater required when using GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Dry ice can form within the flow control openings and cause blockage of shielding gas
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed

48. What does inductance control?
When the filler wire is in direct contract with the base metal
Shielding the molten weld metal from atmospheric contamination
1/4 inch to 1/2 inch
The time rate of response for the current rise and fall

49. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Minutes of elapsed time continually run (out of 10 minutes)
Generally not as accurate
Pressure vessels and the piping industry
Puddle fluidity

50. Give a description of 'pinch effect'
AWS and CSA
Puddle fluidity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The resistace to electrical current flow increases with it. Causing the electrode to heat