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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. List the three methods of metal transfer with GMAW
5.8 to 12.5 L/min
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)

2. Why is a fiber washer required and what cylinder gas requires it?
The Arc voltage
These terms are quite restrictive and often technically incorrect
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode

3. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
AWS and CSA
1/4 inch to 1/2 inch
85%
Gives arc voltage values to the control system of the feeder

4. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube

5. What would be an indication that the drive roll pressure is adjusted correctly?
Voltage is the force that overcomes resistance to allow amperage flow
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone

6. What is the purpose of a regulator and what does it indicate on its gauges?
(DCEP) Direct Current Electrode Positive or Reverse polarity
DCEP (Direct Current Electrode Positive) Reverse Polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Reducing the gas source pressure to a constant working pressure

7. Why must CO2 cylinders be used in the vertical position?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Higher 26 to 35 arc volts

8. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Voltage is the force that overcomes resistance to allow amperage flow
The time rate of response for the current rise and fall
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube

9. List 3 wire drive systems and give a short description of each
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association
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
(DCEP) Direct Current Electrode Positive or Reverse polarity

10. What is another term for electrode holders for GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Guns
Spatter problems and poor weld appearance
Wire feed speed - Voltage control

11. Draw a typical volt amp curve for a machine that is designed for GMAW
20 to 200 times per second
Cause flaking - which can clog the liner and contact tube
...
If you dont know this check your phone

12. What type of power source is used with a constant speed wire feeder?
Cause flaking - which can clog the liner and contact tube
Constant voltage (CV)
85%
Wire feed speed

13. What is the required arc voltage used for short circuit transfer?
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall
12 to 22 arc volts
Aluminum wire

14. 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
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
Wire feed speed

15. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination
3
AWS and CSA

16. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
1/4 inch to 1/2 inch
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
85%

17. In the GMAW process what does amperage control?
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
Speed of the feed motor and - starting / stopping electrode feed
SMAW - GTAW

18. What type of power source is commonly used with a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
85%
Constant current (CC)
Constant- speed wire feeders and Voltage- sennsing wire feeders

19. What does the abbreviation NEMA stand for?
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires
National Electrical Manufactures Association

20. What is the preferred drive roll design for solid wires?
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
These terms are quite restrictive and often technically incorrect
Voltage is the force that overcomes resistance to allow amperage flow

21. What output on the welding machine is used to rate the duty cycle?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
By there current carrying capacity

22. 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
Generally not as accurate
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

23. List the basic equipment requirements for the GMAW process
SMAW - GTAW
Constant voltage (CV)
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

24. In the GMAW process what does voltage control?
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone
Dry ice can form within the flow control openings and cause blockage of shielding gas

25. List several industries that would use GMAW
Wire feed speed - Voltage control
Pressure vessels and the piping industry
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

26. What is the purpose of the shielding gas used in GMAW?
Pressure vessels and the piping industry
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
Shielding the molten weld metal from atmospheric contamination

27. What controls amperage when using GMAW?
Wire feed speed
If you dont know this check your phone
The Arc voltage
Dry ice can form within the flow control openings and cause blockage of shielding gas

28. Give a description of 'pinch effect'
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
If you dont know this check your phone

29. What does a flowmeter do and what does it measure?
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity

30. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Minimum distortion due to low heat input
To prevent leakage - Carbon Dioxide (CO2)
...
Wire feed speed

31. Regulators control_____________ flowmeters SHOW____________.
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

32. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect
The Arc voltage

33. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect
(DCEP) Direct Current Electrode Positive or Reverse polarity

34. How many times per second does short circuiting take place?
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
20 to 200 times per second
Penetration and burn - off rate of the electrode

35. What is the recommended electrode stick- out for .035 solid wire?
Insufficient current to melt the wire off cleanly
Gas metal arc welding
1/4 inch to 1/2 inch
5.8 to 12.5 L/min

36. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
Constant voltage (CV)
National Electrical Manufactures Association

37. What is an advantage of pulsed arc transfer with GMAW?
Gives arc voltage values to the control system of the feeder
The negative side of a welding unit
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

38. Why is a line heater required when using GMAW?
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Dry ice can form within the flow control openings and cause blockage of shielding gas
The negative side of a welding unit

39. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly

40. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Minimum distortion due to low heat input
Pressure vessels and the piping industry
The time rate of response for the current rise and fall
Duty cycle

41. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone

42. When is the metal transferred with short circuit transfer?
Guns
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

43. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
Flux cored wires

44. What effect does increasing and decreasing the inductance have on the weld?
Welding process that joins metals by heating them with an electric arc
Puddle fluidity
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

45. What is the maximum distance that hard wire can be successfully pushed?
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
15 feet (4.5 meters)

46. What happens when the electrode extension is increased?
To limit the short circuiting current so that spatter is reduced
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The resistace to electrical current flow increases with it. Causing the electrode to heat

47. What is the effect of too much slope?
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Insufficient current to melt the wire off cleanly

48. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)
Spatter problems and poor weld appearance

49. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal
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

50. What does inductance control?
Controls the rate of flow of a shielding gas to the gun nozzle
The time rate of response for the current rise and fall
SMAW - GTAW
Constant current (CC)