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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. How are GMAW guns rated?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
SMAW - GTAW

2. Give a description of 'pinch effect'
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas

3. List several industries that would use GMAW
Pressure vessels and the piping industry
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
Duty cycle

4. With straight polarity where is 2/3 of the arc energy?
Higher 26 to 35 arc volts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit

5. What is another term for electrode holders for GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns
Constant current (CC)

6. What does inductance control?
National Electrical Manufactures Association
The time rate of response for the current rise and fall
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding

7. Give a brief description of the GMAW process
Duty cycle
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding process that joins metals by heating them with an electric arc

8. Why is globular transfer generally avoided with GMAW?
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Insufficient current to melt the wire off cleanly
Spatter problems and poor weld appearance

9. What is the purpose of the shielding gas used in GMAW?
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Guns

10. List the three methods of metal transfer with GMAW
SMAW - GTAW
Welding process that joins metals by heating them with an electric arc
When the filler wire is in direct contract with the base metal
Short- circuiting transfer - Globular transfer - Spray transfer

11. What controls the wire speed on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

12. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Reducing the gas source pressure to a constant working pressure
15 feet (4.5 meters)
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle

13. Why must CO2 cylinders be used in the vertical position?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

14. What is a typical flow rate of CO2 for short circuit transfer?
...
20 to 200 times per second
5.8 to 12.5 L/min
When the filler wire is in direct contract with the base metal

15. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Reducing the gas source pressure to a constant working pressure
(DCEP) Direct Current Electrode Positive or Reverse polarity
20 to 200 times per second
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

16. List the factors that determine the mode of metal transfer
Pressure - The rate of flow of a shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
AWS and CSA

17. What current and polarity is generally used with GMAW?
These terms are quite restrictive and often technically incorrect
The time rate of response for the current rise and fall
DCEP (Direct Current Electrode Positive) Reverse Polarity
...

18. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

19. What is the required arc voltage used for short circuit transfer?
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone

20. What is the main purpose of 'slope'?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
1/4 inch to 1/2 inch

21. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding

22. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
The Arc voltage

23. List the basic equipment requirements for the GMAW process
Duty cycle
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Motor driven generators - Transformer rectifiers - and Inverter designs

24. 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)
Motor driven generators - Transformer rectifiers - and Inverter designs
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
Penetration and burn - off rate of the electrode

25. What controls amperage when using GMAW?
Pressure vessels and the piping industry
Wire feed speed
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder

26. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
If you dont know this check your phone

27. Why is a fiber washer required and what cylinder gas requires it?
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall
Pressure vessels and the piping industry

28. What does voltage do in an electrical circuit?
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent drawing of liquid CO2 (Carbon Dioxide)

29. What wire are knurled drive rolls most commonly used on?
Flux cored wires
To limit the short circuiting current so that spatter is reduced
The negative side of a welding unit
Higher 26 to 35 arc volts

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)

31. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Reducing the gas source pressure to a constant working pressure

32. 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)
To prevent leakage - Carbon Dioxide (CO2)
85%

33. List 3 wire drive systems and give a short description of each
(DCEP) Direct Current Electrode Positive or Reverse polarity
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
These terms are quite restrictive and often technically incorrect

34. What happens when the electrode extension is increased?
The negative side of a welding unit
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate

35. 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
The time rate of response for the current rise and fall
85%
Gas metal arc welding

36. What does the abbreviation NEMA stand for?
Constant current (CC)
12 to 22 arc volts
National Electrical Manufactures Association
Flux cored wires

37. 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
To prevent leakage - Carbon Dioxide (CO2)
Pressure vessels and the piping industry
Shielding the molten weld metal from atmospheric contamination

38. How many times per second does short circuiting take place?
Minimum distortion due to low heat input
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

39. What is the recommended electrode stick- out for .035 solid wire?
AWS and CSA
1/4 inch to 1/2 inch
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

40. What does the term GMAW identify?
20 to 200 times per second
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Gas metal arc welding

41. Regulators control_____________ flowmeters SHOW____________.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a shielding gas

42. What does the wire feeder control?
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
Speed of the feed motor and - starting / stopping electrode feed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

43. What is the preferred drive roll design for solid wires?
To prevent leakage - Carbon Dioxide (CO2)
V groove or U groove
Penetration and burn - off rate of the electrode
Constant voltage (CV)

44. What 2 controls are found on a GMAW set- up?
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

45. What processes are constant current (CC) power sources designed to be used with?
Constant- speed wire feeders and Voltage- sennsing wire feeders
SMAW - GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs
Spatter problems and poor weld appearance

46. A pull type drive system is usually used on what type of material?
Generally not as accurate
Aluminum wire
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gives arc voltage values to the control system of the feeder

47. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Constant voltage (CV)
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control

48. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

49. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

50. What power sources are used with the GMAW Process?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Insufficient current to melt the wire off cleanly
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas