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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 machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
When the filler wire is in direct contract with the base metal
3
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode

2. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
The Arc voltage
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

3. What does the term GMAW identify?
Reducing the gas source pressure to a constant working pressure
Gas metal arc welding
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)

4. What does a flowmeter do and what does it measure?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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
Controls the rate of flow of a shielding gas to the gun nozzle

5. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
...
The time rate of response for the current rise and fall

6. Why must CO2 cylinders be used in the vertical position?
To prevent leakage - Carbon Dioxide (CO2)
Generally not as accurate
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)

7. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Aluminum wire
To limit the short circuiting current so that spatter is reduced
Minutes of elapsed time continually run (out of 10 minutes)

8. What controls amperage when using GMAW?
The Arc voltage
SMAW - GTAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed

9. Why is globular transfer generally avoided with GMAW?
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance
Pressure vessels and the piping industry
...

10. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

11. List the three methods of metal transfer with GMAW
Aluminum wire
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
Short- circuiting transfer - Globular transfer - Spray transfer

12. What does inductance control?
SMAW - GTAW
Voltage is the force that overcomes resistance to allow amperage flow
The time rate of response for the current rise and fall
When the filler wire is in direct contract with the base metal

13. 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)
...
Insufficient current to melt the wire off cleanly

14. What 2 organizations designate specifications for GMAW wires?
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
The negative side of a welding unit
AWS and CSA

15. In the GMAW process what does amperage control?
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode

16. What does the abbreviation NEMA stand for?
Gives arc voltage values to the control system of the feeder
Flux cored wires
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association

17. Give a brief description of the GMAW process
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding process that joins metals by heating them with an electric arc
...
Spatter problems and poor weld appearance

18. A pull type drive system is usually used on what type of material?
Aluminum wire
To prevent drawing of liquid CO2 (Carbon Dioxide)
By there current carrying capacity
Gas metal arc welding

19. What processes are constant current (CC) power sources designed to be used with?
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

20. Give a description of 'pinch effect'
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Generally not as accurate

21. How many times per second does short circuiting take place?
Puddle fluidity
20 to 200 times per second
Shielding the molten weld metal from atmospheric contamination
Minimum distortion due to low heat input

22. List 3 wire drive systems and give a short description of each
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Penetration and burn - off rate of the electrode
Pressure vessels and the piping industry

23. What wire are knurled drive rolls most commonly used on?
3
These terms are quite restrictive and often technically incorrect
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

24. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
SMAW - GTAW
AWS and CSA

25. What does voltage do in an electrical circuit?
15 feet (4.5 meters)
Guns
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry

26. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
DCEP (Direct Current Electrode Positive) Reverse Polarity
SMAW - GTAW
By there current carrying capacity

27. 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
V groove or U groove
When the filler wire is in direct contract with the base metal
Higher 26 to 35 arc volts

28. What is the required arc voltage used for short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts

29. What controls the wire speed on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Penetration and burn - off rate of the electrode
The Arc voltage
Motor driven generators - Transformer rectifiers - and Inverter designs

30. What is the key advantage of short circuiting transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
1/4 inch to 1/2 inch
Flux cored wires
Minimum distortion due to low heat input

31. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity

32. What type of power source is used with a constant speed wire feeder?
Controls the rate of flow of a shielding gas to the gun nozzle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant voltage (CV)
Aluminum wire

33. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
3
Speed of the feed motor and - starting / stopping electrode feed

34. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
If you dont know this check your phone
85%
Gives arc voltage values to the control system of the feeder
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

35. Why is a fiber washer required and what cylinder gas requires it?
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance
To prevent leakage - Carbon Dioxide (CO2)
Aluminum wire

36. List several industries that would use GMAW
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Controls the rate of flow of a shielding gas to the gun nozzle

37. What is another term for electrode holders for GMAW?
Generally not as accurate
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Guns

38. With straight polarity where is 2/3 of the arc energy?
85%
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
Duty cycle

39. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
85%
Gives arc voltage values to the control system of the feeder

40. What type of power source is commonly used with a voltage sensing wire feeder?
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
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
Constant current (CC)

41. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
85%
The negative side of a welding unit

42. What are the 2 types of wire feeders available?
Reducing the gas source pressure to a constant working pressure
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone

43. How are GMAW guns rated?
By there current carrying capacity
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
15 feet (4.5 meters)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

44. Draw a typical volt amp curve for a machine that is designed for GMAW
3
85%
If you dont know this check your phone
The Arc voltage

45. What is a typical flow rate of CO2 for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas
3

46. What is the preferred drive roll design for solid wires?
V groove or U groove
Higher 26 to 35 arc volts
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced

47. 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
The negative side of a welding unit
Minutes of elapsed time continually run (out of 10 minutes)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

48. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas
Aluminum wire

49. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
The Arc voltage
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
When the filler wire is in direct contract with the base metal

50. Regulators control_____________ flowmeters SHOW____________.
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts