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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. What is a solenoid valve and what actuates it?
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

2. A 10 minute cycle of welding time vs cooling time a given machine can handle.
12 to 22 arc volts
Aluminum wire
Duty cycle
The negative side of a welding unit

3. In the GMAW process what does voltage control?
Penetration and burn - off rate of the electrode
To limit the short circuiting current so that spatter is reduced
Puddle fluidity
By there current carrying capacity

4. What does inductance control?
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)

5. What current and polarity is generally used with GMAW?
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

6. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
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
When the filler wire is in direct contract with the base metal
(DCEP) Direct Current Electrode Positive or Reverse polarity

7. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW
The Arc voltage

8. What controls the wire speed on a voltage sensing wire feeder?
SMAW - GTAW
85%
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle

9. Why is globular transfer generally avoided with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)

10. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Wire feed speed - Voltage control
Generally not as accurate
Wire feed speed
SMAW - GTAW

11. What does the abbreviation NEMA stand for?
Constant current (CC)
National Electrical Manufactures Association
SMAW - GTAW
Flux cored wires

12. When is the metal transferred with short circuit transfer?
AWS and CSA
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
SMAW - GTAW

13. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Guns
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
V groove or U groove
Cause flaking - which can clog the liner and contact tube

14. What is the maximum distance that hard wire can be successfully pushed?
Flux cored wires
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
15 feet (4.5 meters)
Constant voltage (CV)

15. List several industries that would use GMAW
The time rate of response for the current rise and fall
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
National Electrical Manufactures Association

16. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Pressure - The rate of flow of a shielding gas
The Arc voltage
Gives arc voltage values to the control system of the feeder

17. In the GMAW process what does amperage control?
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Penetration and burn - off rate of the electrode

18. What is the purpose of a regulator and what does it indicate on its gauges?
...
Flux cored wires
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure

19. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

20. What is an advantage of pulsed arc transfer with GMAW?
When the filler wire is in direct contract with the base metal
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

21. What processes are constant current (CC) power sources designed to be used with?
Gives arc voltage values to the control system of the feeder
SMAW - GTAW
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
5.8 to 12.5 L/min

22. What type of power source is used with a constant speed wire feeder?
Duty cycle
If you dont know this check your phone
Constant voltage (CV)
Spatter problems and poor weld appearance

23. What controls amperage when using GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed

24. Why is the term GMAW preferred over MIG or MAG?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

25. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
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
National Electrical Manufactures Association

26. What is the purpose of the shielding gas used in GMAW?
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
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc

27. What effect does increasing and decreasing the inductance have on the weld?
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant voltage (CV)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

28. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
...

29. A pull type drive system is usually used on what type of material?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed
Aluminum wire
AWS and CSA

30. How many times per second does short circuiting take place?
20 to 200 times per second
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control

31. What is the preferred drive roll design for solid wires?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
Short- circuiting transfer - Globular transfer - Spray transfer

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

33. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc
3
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

34. What 2 organizations designate specifications for GMAW wires?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA
3
Constant current (CC)

35. List the three methods of metal transfer with GMAW
Pressure - The rate of flow of a shielding gas
Pressure vessels and the piping industry
Short- circuiting transfer - Globular transfer - Spray transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity

36. What type of power source is commonly used with a voltage sensing wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant current (CC)

37. What happens when the electrode extension is increased?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The resistace to electrical current flow increases with it. Causing the electrode to heat
The time rate of response for the current rise and fall
To prevent drawing of liquid CO2 (Carbon Dioxide)

38. What wire are knurled drive rolls most commonly used on?
Insufficient current to melt the wire off cleanly
Spatter problems and poor weld appearance
Flux cored wires
Pressure vessels and the piping industry

39. What are the 2 types of wire feeders available?
Wire feed speed
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant current (CC)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

40. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
To limit the short circuiting current so that spatter is reduced
3
Aluminum wire

41. What is the effect of too much slope?
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Insufficient current to melt the wire off cleanly
If you dont know this check your phone

42. What does a flowmeter do and what does it measure?
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders

43. List 3 forms compressed gases may be supplied for welding
AWS and CSA
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Spatter problems and poor weld appearance

44. Give a description of 'pinch effect'
Cause flaking - which can clog the liner and contact tube
Insufficient current to melt the wire off cleanly
The negative side of a welding unit
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

45. What is the recommended electrode stick- out for .035 solid wire?
V groove or U groove
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
1/4 inch to 1/2 inch

46. Draw a typical volt amp curve for a machine that is designed for GMAW
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure - The rate of flow of a shielding gas

47. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Wire feed speed
The time rate of response for the current rise and fall
Minimum distortion due to low heat input

48. What is the main purpose of 'slope'?
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
Constant current (CC)

49. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
The resistace to electrical current flow increases with it. Causing the electrode to heat

50. What output on the welding machine is used to rate the duty cycle?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly