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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. In the GMAW process what does voltage control?
To limit the short circuiting current so that spatter is reduced
3
Puddle fluidity
Gas metal arc welding

2. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas
If you dont know this check your phone
20 to 200 times per second

3. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
To prevent leakage - Carbon Dioxide (CO2)
Cause flaking - which can clog the liner and contact tube
Wire feed speed
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

4. What is the main purpose of 'slope'?
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
Higher 26 to 35 arc volts

5. With straight polarity where is 2/3 of the arc energy?
Higher 26 to 35 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
The negative side of a welding unit

6. 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
(DCEP) Direct Current Electrode Positive or Reverse polarity
...

7. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
V groove or U groove
Gives arc voltage values to the control system of the feeder
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

8. What happens when the electrode extension is increased?
Duty cycle
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
National Electrical Manufactures Association

9. What power sources are used with the GMAW Process?
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced

10. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Dry ice can form within the flow control openings and cause blockage of shielding gas
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Aluminum wire

11. List 3 forms compressed gases may be supplied for welding
Dry ice can form within the flow control openings and cause blockage of shielding gas
By there current carrying capacity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association

12. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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The Arc voltage
Wire feed speed - Voltage control
Generally not as accurate

13. What is a typical flow rate of CO2 for short circuit transfer?
Higher 26 to 35 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
5.8 to 12.5 L/min
National Electrical Manufactures Association

14. What does inductance control?
Penetration and burn - off rate of the electrode
V groove or U groove
The time rate of response for the current rise and fall
Gas metal arc welding

15. What would be an indication that the drive roll pressure is adjusted correctly?
Welding process that joins metals by heating them with an electric arc
By there current carrying capacity
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)

16. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Dry ice can form within the flow control openings and cause blockage of shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal

17. What type of power source is commonly used with a voltage sensing wire feeder?
Short- circuiting transfer - Globular transfer - Spray transfer
Flux cored wires
Constant current (CC)
DCEP (Direct Current Electrode Positive) Reverse Polarity

18. When is the metal transferred with short circuit transfer?
Penetration and burn - off rate of the electrode
20 to 200 times per second
Wire feed speed - Voltage control
When the filler wire is in direct contract with the base metal

19. Why is a line heater required when using GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove
3

20. What is the required arc voltage used for short circuit transfer?
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Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
12 to 22 arc volts

21. What does the wire feeder control?
Minimum distortion due to low heat input
Guns
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity

22. What are the 2 types of wire feeders available?
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders

23. What controls amperage when using GMAW?
Wire feed speed
Generally not as accurate
85%
Minimum distortion due to low heat input

24. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Constant current (CC)
Flux cored wires
Aluminum wire

25. Draw a typical volt amp curve for a machine that is designed for GMAW
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
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

26. What is another term for electrode holders for GMAW?
Guns
20 to 200 times per second
Puddle fluidity
If you dont know this check your phone

27. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat

28. Give a brief description of the GMAW process
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow

29. What is the purpose of the shielding gas used in GMAW?
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance

30. Regulators control_____________ flowmeters SHOW____________.
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
Higher 26 to 35 arc volts

31. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
By there current carrying capacity
20 to 200 times per second
The negative side of a welding unit

32. Why is globular transfer generally avoided with GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Spatter problems and poor weld appearance
1/4 inch to 1/2 inch

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)

34. What processes are constant current (CC) power sources designed to be used with?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure vessels and the piping industry
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced

35. What is the maximum distance that hard wire can be successfully pushed?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
V groove or U groove
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What is the effect of too much slope?
AWS and CSA
Generally not as accurate
1/4 inch to 1/2 inch
Insufficient current to melt the wire off cleanly

37. How many times per second does short circuiting take place?
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts

38. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs

39. In the GMAW process what does amperage control?
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
20 to 200 times per second
Penetration and burn - off rate of the electrode

40. What does a flowmeter do and what does it measure?
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer

41. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Duty cycle
Reducing the gas source pressure to a constant working pressure
To prevent leakage - Carbon Dioxide (CO2)

42. How are GMAW guns rated?
Constant current (CC)
Minutes of elapsed time continually run (out of 10 minutes)
By there current carrying capacity
Aluminum wire

43. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
...
Wire feed speed - Voltage control

44. What is a solenoid valve and what actuates it?
Spatter problems and poor weld appearance
If you dont know this check your phone
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

45. A pull type drive system is usually used on what type of material?
1/4 inch to 1/2 inch
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance
Aluminum wire

46. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
If you dont know this check your phone
Gas metal arc welding
When the filler wire is in direct contract with the base metal

47. What type of power source is used with a constant speed wire feeder?
Wire feed speed - Voltage control
Constant voltage (CV)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires

48. 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
15 feet (4.5 meters)
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

49. List the basic equipment requirements for the GMAW process
Wire feed speed - Voltage control
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
To limit the short circuiting current so that spatter is reduced

50. 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
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)
85%