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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. Regulators control_____________ flowmeters SHOW____________.
Guns
Reducing the gas source pressure to a constant working pressure
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

2. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Gas metal arc welding
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed

3. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
1/4 inch to 1/2 inch
3
Dry ice can form within the flow control openings and cause blockage of shielding gas
5.8 to 12.5 L/min

4. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Constant current (CC)
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity

5. How are GMAW guns rated?
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

6. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Minimum distortion due to low heat input
Wire feed speed - Voltage control
3

7. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Guns
...
Constant- speed wire feeders and Voltage- sennsing wire feeders

8. When is the metal transferred with short circuit transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders

9. List 3 wire drive systems and give a short description of each
To limit the short circuiting current so that spatter is reduced
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
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min

10. What is the required arc voltage used for short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
12 to 22 arc volts
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

11. 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
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
The Arc voltage
Pressure vessels and the piping industry

12. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination

13. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Guns
Generally not as accurate
Duty cycle
By there current carrying capacity

14. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
These terms are quite restrictive and often technically incorrect
Controls the rate of flow of a shielding gas to the gun nozzle
Guns
Higher 26 to 35 arc volts

15. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
Shielding the molten weld metal from atmospheric contamination

16. What is the main purpose of 'slope'?
Wire feed speed
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
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association

17. What is the purpose of the shielding gas used in GMAW?
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
Shielding the molten weld metal from atmospheric contamination
Flux cored wires

18. How many times per second does short circuiting take place?
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
Generally not as accurate

19. What happens when the electrode extension is increased?
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The time rate of response for the current rise and fall

20. 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
The Arc voltage
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Controls the rate of flow of a shielding gas to the gun nozzle

21. What controls the wire speed on a voltage sensing wire feeder?
20 to 200 times per second
Shielding the molten weld metal from atmospheric contamination
The Arc voltage
Spatter problems and poor weld appearance

22. What is the maximum distance that hard wire can be successfully pushed?
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs

23. What does a flowmeter do and what does it measure?
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect

24. List several industries that would use GMAW
National Electrical Manufactures Association
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
Wire feed speed - Voltage control

25. What type of power source is commonly used with a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
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 current (CC)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

26. What does inductance control?
1/4 inch to 1/2 inch
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
By there current carrying capacity
The time rate of response for the current rise and fall

27. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)
85%

28. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
By there current carrying capacity
If you dont know this check your phone
Minimum distortion due to low heat input
Welding process that joins metals by heating them with an electric arc

29. What wire are knurled drive rolls most commonly used on?
...
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
(DCEP) Direct Current Electrode Positive or Reverse polarity

30. What controls amperage when using GMAW?
Wire feed speed
Duty cycle
When the filler wire is in direct contract with the base metal
Puddle fluidity

31. 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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gas metal arc welding
If you dont know this check your phone

32. Why is the term GMAW preferred over MIG or MAG?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch

33. What effect does increasing and decreasing the inductance have on the weld?
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3

34. List 3 forms compressed gases may be supplied for welding
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

35. What 2 organizations designate specifications for GMAW wires?
SMAW - GTAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
AWS and CSA
Pressure - The rate of flow of a shielding gas

36. What would be an indication that the drive roll pressure is adjusted correctly?
Cause flaking - which can clog the liner and contact tube
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

37. In the GMAW process what does amperage control?
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode

38. What are the 2 types of wire feeders available?
Duty cycle
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns

39. Give a description of 'pinch effect'
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
Spatter problems and poor weld appearance
Generally not as accurate

40. A 10 minute cycle of welding time vs cooling time a given machine can handle.
To prevent drawing of liquid CO2 (Carbon Dioxide)
20 to 200 times per second
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle

41. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association

42. What is the preferred drive roll design for solid wires?
Wire feed speed - Voltage control
Pressure vessels and the piping industry
V groove or U groove
By there current carrying capacity

43. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Higher 26 to 35 arc volts
Flux cored wires
If you dont know this check your phone

44. Why is globular transfer generally avoided with GMAW?
By there current carrying capacity
Spatter problems and poor weld appearance
Minimum distortion due to low heat input
Guns

45. What is a typical flow rate of CO2 for short circuit transfer?
V groove or U groove
Spatter problems and poor weld appearance
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

46. What is the key advantage of short circuiting transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input
Gas metal arc welding

47. Why is a fiber washer required and what cylinder gas requires it?
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed
15 feet (4.5 meters)

48. 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
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch

49. What does the term GMAW identify?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gas metal arc welding
Pressure - The rate of flow of a shielding gas

50. What does the wire feeder control?
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders