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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 the disadvantage of the gauge preset type of regulator/flowmeter?
12 to 22 arc volts
85%
Generally not as accurate
Flux cored wires

2. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit

3. What are the 2 types of wire feeders available?
SMAW - GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal
1/4 inch to 1/2 inch

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Gives arc voltage values to the control system of the feeder
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle

5. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Pressure - The rate of flow of a shielding gas
The negative side of a welding unit
...

6. 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
If you dont know this check your phone
20 to 200 times per second

7. What is a solenoid valve and what actuates it?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone

8. What effect does increasing and decreasing the inductance have on the weld?
Constant current (CC)
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)
Minutes of elapsed time continually run (out of 10 minutes)

9. What power sources are used with the GMAW Process?
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
Motor driven generators - Transformer rectifiers - and Inverter designs

10. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity
These terms are quite restrictive and often technically incorrect

11. 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
Pressure - The rate of flow of a shielding gas
Flux cored wires

12. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Flux cored wires
The resistace to electrical current flow increases with it. Causing the electrode to heat
3
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)

14. A pull type drive system is usually used on what type of material?
Aluminum wire
Gas metal arc welding
The time rate of response for the current rise and fall
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15. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Gas metal arc welding
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association

16. Why must CO2 cylinders be used in the vertical position?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc

17. What does the wire feeder control?
Shielding the molten weld metal from atmospheric contamination
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc

18. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Constant current (CC)
If you dont know this check your phone
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

19. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Insufficient current to melt the wire off cleanly
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
Voltage is the force that overcomes resistance to allow amperage flow

20. What happens when the electrode extension is increased?
Puddle fluidity
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat

21. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
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
Controls the rate of flow of a shielding gas to the gun nozzle

22. Regulators control_____________ flowmeters SHOW____________.
Puddle fluidity
The Arc voltage
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas

23. What is the recommended electrode stick- out for .035 solid wire?
Speed of the feed motor and - starting / stopping electrode feed
20 to 200 times per second
Insufficient current to melt the wire off cleanly
1/4 inch to 1/2 inch

24. List 3 forms compressed gases may be supplied for welding
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

25. What processes are constant current (CC) power sources designed to be used with?
Constant current (CC)
When the filler wire is in direct contract with the base metal
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW

26. How many times per second does short circuiting take place?
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second
When the filler wire is in direct contract with the base metal

27. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)

28. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
(DCEP) Direct Current Electrode Positive or Reverse polarity

29. List the three methods of metal transfer with GMAW
3
Short- circuiting transfer - Globular transfer - Spray transfer
By there current carrying capacity
The negative side of a welding unit

30. What is the maximum distance that hard wire can be successfully pushed?
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
15 feet (4.5 meters)

31. What is an advantage of pulsed arc transfer with GMAW?
Shielding the molten weld metal from atmospheric contamination
3
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

32. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle
Gas metal arc welding
Penetration and burn - off rate of the electrode

33. What does inductance control?
Gas metal arc welding
The time rate of response for the current rise and fall
Constant voltage (CV)
(DCEP) Direct Current Electrode Positive or Reverse polarity

34. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
Flux cored wires
20 to 200 times per second

35. What current and polarity is generally used with GMAW?
The Arc voltage
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly

36. List several industries that would use GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
Puddle fluidity
...
Pressure vessels and the piping industry

37. When is the metal transferred with short circuit transfer?
Aluminum wire
Wire feed speed
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder

38. What 2 controls are found on a GMAW set- up?
DCEP (Direct Current Electrode Positive) Reverse Polarity
1/4 inch to 1/2 inch
Wire feed speed - Voltage control
When the filler wire is in direct contract with the base metal

39. With straight polarity where is 2/3 of the arc energy?
Gas metal arc welding
Gives arc voltage values to the control system of the feeder
The negative side of a welding unit
3

40. What is the main purpose of 'slope'?
Wire feed speed - Voltage control
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
Welding process that joins metals by heating them with an electric arc

41. Give a description of 'pinch effect'
Pressure - The rate of flow of a shielding gas
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow

42. What is another term for electrode holders for GMAW?
These terms are quite restrictive and often technically incorrect
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
3

43. What does the abbreviation NEMA stand for?
3
National Electrical Manufactures Association
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Pressure - The rate of flow of a shielding gas

44. Draw a typical volt amp curve for a machine that is designed for GMAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%

45. Why is globular transfer generally avoided with GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance
20 to 200 times per second
Pressure - The rate of flow of a shielding gas

46. What is the preferred drive roll design for solid wires?
To prevent leakage - Carbon Dioxide (CO2)
Cause flaking - which can clog the liner and contact tube
V groove or U groove
Gives arc voltage values to the control system of the feeder

47. What is the purpose of the shielding gas used in GMAW?
Generally not as accurate
12 to 22 arc volts
Shielding the molten weld metal from atmospheric contamination
Spatter problems and poor weld appearance

48. What output on the welding machine is used to rate the duty cycle?
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)

49. How are GMAW guns rated?
By there current carrying capacity
Generally not as accurate
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity

50. What 2 organizations designate specifications for GMAW wires?
Pressure vessels and the piping industry
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
AWS and CSA
12 to 22 arc volts