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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 output on the welding machine is used to rate the duty cycle?
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat
To limit the short circuiting current so that spatter is reduced

2. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube

3. What does the term GMAW identify?
Gas metal arc welding
Duty cycle
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure

4. Give a description of 'pinch effect'
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. What current and polarity is generally used with GMAW?
SMAW - GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
National Electrical Manufactures Association
Constant- speed wire feeders and Voltage- sennsing wire feeders

6. What is the effect of too much slope?
If you dont know this check your phone
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
These terms are quite restrictive and often technically incorrect

7. What would be an indication that the drive roll pressure is adjusted correctly?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

8. What does the wire feeder control?
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder

9. How many times per second does short circuiting take place?
Insufficient current to melt the wire off cleanly
20 to 200 times per second
Wire feed speed
When the filler wire is in direct contract with the base metal

10. What does a flowmeter do and what does it measure?
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced

11. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Insufficient current to melt the wire off cleanly
3
Constant voltage (CV)
20 to 200 times per second

12. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
85%
Constant voltage (CV)

13. What wire are knurled drive rolls most commonly used on?
5.8 to 12.5 L/min
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires

14. What is the main purpose of 'slope'?
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination

15. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Penetration and burn - off rate of the electrode
...
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
3

16. What is another term for electrode holders for GMAW?
...
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
Guns

17. In the GMAW process what does voltage control?
National Electrical Manufactures Association
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs

18. Why must CO2 cylinders be used in the vertical position?
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. What type of power source is used with a constant speed wire feeder?
Higher 26 to 35 arc volts
Constant voltage (CV)
Voltage is the force that overcomes resistance to allow amperage flow
...

20. What type of power source is commonly used with a voltage sensing wire feeder?
Flux cored wires
Constant current (CC)
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

21. What is the key advantage of short circuiting transfer?
The Arc voltage
Minimum distortion due to low heat input
Pressure vessels and the piping industry
SMAW - GTAW

22. List the basic equipment requirements for the GMAW process
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Aluminum wire
15 feet (4.5 meters)

23. List 3 wire drive systems and give a short description of each
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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 to 200 times per second

24. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone
The Arc voltage
To prevent drawing of liquid CO2 (Carbon Dioxide)

25. A pull type drive system is usually used on what type of material?
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control
Aluminum wire
Cause flaking - which can clog the liner and contact tube

26. 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
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube

27. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Flux cored wires
1/4 inch to 1/2 inch
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity

28. Regulators control_____________ flowmeters SHOW____________.
Aluminum wire
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow

29. What is a typical flow rate of CO2 for short circuit transfer?
Insufficient current to melt the wire off cleanly
5.8 to 12.5 L/min
V groove or U groove
Welding process that joins metals by heating them with an electric arc

30. Give a brief description of the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding process that joins metals by heating them with an electric arc
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders

31. Why is a line heater required when using GMAW?
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode

32. What is the purpose of the shielding gas used in GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

33. What happens when the electrode extension is increased?
These terms are quite restrictive and often technically incorrect
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
To limit the short circuiting current so that spatter is reduced

34. Draw a typical volt amp curve for a machine that is designed for GMAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
...
If you dont know this check your phone
Constant current (CC)

35. With straight polarity where is 2/3 of the arc energy?
3
Pressure - The rate of flow of a shielding gas
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

36. What controls the wire speed on a voltage sensing wire feeder?
Cause flaking - which can clog the liner and contact tube
The Arc voltage
15 feet (4.5 meters)
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

37. What controls amperage when using GMAW?
Minimum distortion due to low heat input
Flux cored wires
Wire feed speed
To prevent drawing of liquid CO2 (Carbon Dioxide)

38. List the factors that determine the mode of metal transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

39. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Welding process that joins metals by heating them with an electric arc
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
Reducing the gas source pressure to a constant working pressure

40. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder
Generally not as accurate

41. What is the required arc voltage used for short circuit transfer?
Higher 26 to 35 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
12 to 22 arc volts
Minutes of elapsed time continually run (out of 10 minutes)

42. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle
Flux cored wires
V groove or U groove

43. What 2 controls are found on a GMAW set- up?
Constant current (CC)
Wire feed speed - Voltage control
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

44. What is the maximum distance that hard wire can be successfully pushed?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The negative side of a welding unit
15 feet (4.5 meters)
DCEP (Direct Current Electrode Positive) Reverse Polarity

45. What is the preferred drive roll design for solid wires?
V groove or U groove
Pressure vessels and the piping industry
Gas metal arc welding
Constant current (CC)

46. What processes are constant current (CC) power sources designed to be used with?
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW

47. What is an advantage of pulsed arc transfer with GMAW?
Minimum distortion due to low heat input
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
National Electrical Manufactures Association
AWS and CSA

48. What is the disadvantage of the gauge preset type of regulator/flowmeter?
5.8 to 12.5 L/min
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Generally not as accurate

49. What does voltage do in an electrical circuit?
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
Guns
Wire feed speed

50. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle