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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. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
3
20 to 200 times per second
The time rate of response for the current rise and fall

2. What is the effect of too much slope?
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Gives arc voltage values to the control system of the feeder
Aluminum wire
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Pressure vessels and the piping industry

4. Why is the term GMAW preferred over MIG or MAG?
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
V groove or U groove
Constant current (CC)

5. What controls amperage when using GMAW?
12 to 22 arc volts
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs

6. Give a brief description of the GMAW process
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Welding process that joins metals by heating them with an electric arc
Gas metal arc welding
Higher 26 to 35 arc volts

7. In the GMAW process what does amperage control?
AWS and CSA
Constant current (CC)
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly

8. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

9. What is the main purpose of 'slope'?
3
The time rate of response for the current rise and fall
To limit the short circuiting current so that spatter is reduced
Higher 26 to 35 arc volts

10. What is the required arc voltage used for short circuit transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
12 to 22 arc volts
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders

11. Give a description of 'pinch effect'
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant voltage (CV)
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

12. When is the metal transferred with short circuit transfer?
3
Wire feed speed - Voltage control
When the filler wire is in direct contract with the base metal
National Electrical Manufactures Association

13. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
By there current carrying capacity
Speed of the feed motor and - starting / stopping electrode feed
Cause flaking - which can clog the liner and contact tube
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

14. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
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DCEP (Direct Current Electrode Positive) Reverse Polarity
SMAW - GTAW

15. What current and polarity is generally used with GMAW?
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity
Cause flaking - which can clog the liner and contact tube
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

16. What processes are constant current (CC) power sources designed to be used with?
Puddle fluidity
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
SMAW - GTAW

17. A pull type drive system is usually used on what type of material?
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min
Aluminum wire
Speed of the feed motor and - starting / stopping electrode feed

18. What is the purpose of the shielding gas used in GMAW?
Short- circuiting transfer - Globular transfer - Spray transfer
Flux cored wires
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. 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
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc
12 to 22 arc volts

20. Draw a typical volt amp curve for a machine that is designed for GMAW
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
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1/4 inch to 1/2 inch

21. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
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These terms are quite restrictive and often technically incorrect
Minimum distortion due to low heat input

22. List the three methods of metal transfer with GMAW
20 to 200 times per second
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer

23. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
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

24. How are GMAW guns rated?
By there current carrying capacity
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle

25. What effect does increasing and decreasing the inductance have on the weld?
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Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

26. What does voltage do in an electrical circuit?
Constant current (CC)
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow

27. Regulators control_____________ flowmeters SHOW____________.
When the filler wire is in direct contract with the base metal
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow

28. What is the key advantage of short circuiting transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The time rate of response for the current rise and fall
If you dont know this check your phone
Minimum distortion due to low heat input

29. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect

30. What is the purpose of a regulator and what does it indicate on its gauges?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Reducing the gas source pressure to a constant working pressure
Speed of the feed motor and - starting / stopping electrode feed
Welding process that joins metals by heating them with an electric arc

31. Why is a fiber washer required and what cylinder gas requires it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent leakage - Carbon Dioxide (CO2)
Gas metal arc welding
3

32. What 2 organizations designate specifications for GMAW wires?
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
When the filler wire is in direct contract with the base metal

33. In the GMAW process what does voltage control?
Gas metal arc welding
Wire feed speed - Voltage control
Puddle fluidity
Insufficient current to melt the wire off cleanly

34. What is the preferred drive roll design for solid wires?
Wire feed speed - Voltage control
V groove or U groove
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal

35. What output on the welding machine is used to rate the duty cycle?
Cause flaking - which can clog the liner and contact tube
Minutes of elapsed time continually run (out of 10 minutes)
5.8 to 12.5 L/min
...

36. List several industries that would use GMAW
Motor driven generators - Transformer rectifiers - and Inverter designs
3
Pressure vessels and the piping industry
Puddle fluidity

37. 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
AWS and CSA
Wire feed speed - Voltage control
20 to 200 times per second

38. What is the disadvantage of the gauge preset type of regulator/flowmeter?
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
Duty cycle
Generally not as accurate

39. What is the recommended electrode stick- out for .035 solid wire?
Pressure vessels and the piping industry
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
1/4 inch to 1/2 inch
SMAW - GTAW

40. How many times per second does short circuiting take place?
20 to 200 times per second
Welding process that joins metals by heating them with an electric arc
Flux cored wires
Gas metal arc welding

41. What are the 2 types of wire feeders available?
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders

42. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer
85%
Speed of the feed motor and - starting / stopping electrode feed

43. What 2 controls are found on a GMAW set- up?
Generally not as accurate
Wire feed speed - Voltage control
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect

44. Why must CO2 cylinders be used in the vertical position?
If you dont know this check your phone
...
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder

45. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
V groove or U groove
Dry ice can form within the flow control openings and cause blockage of shielding gas

46. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube

47. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder
V groove or U groove

48. What would be an indication that the drive roll pressure is adjusted correctly?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
Aluminum wire

49. What does inductance control?
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The time rate of response for the current rise and fall

50. List the basic equipment requirements for the GMAW process
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground