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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 output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

2. What controls amperage when using GMAW?
Guns
3
Wire feed speed
Aluminum wire

3. What is the purpose of the shielding gas used in GMAW?
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination
Duty cycle
Flux cored wires

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Flux cored wires
Duty cycle
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

5. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube
Voltage is the force that overcomes resistance to allow amperage flow

6. Why is globular transfer generally avoided with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
3
Spatter problems and poor weld appearance
20 to 200 times per second

7. What is an advantage of pulsed arc transfer with 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
Reducing the gas source pressure to a constant working pressure
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

8. What is the preferred drive roll design for solid wires?
If you dont know this check your phone
Duty cycle
V groove or U groove
National Electrical Manufactures Association

9. What is the disadvantage of the gauge preset type of regulator/flowmeter?
National Electrical Manufactures Association
The Arc voltage
Insufficient current to melt the wire off cleanly
Generally not as accurate

10. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas

11. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant voltage (CV)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Voltage is the force that overcomes resistance to allow amperage flow

12. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant voltage (CV)
Motor driven generators - Transformer rectifiers - and Inverter designs

13. Give a brief description of the GMAW process
Wire feed speed
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc

14. What effect does increasing and decreasing the inductance have on the weld?
Cause flaking - which can clog the liner and contact tube
AWS and CSA
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow

15. What is the recommended electrode stick- out for .035 solid wire?
Insufficient current to melt the wire off cleanly
Constant- speed wire feeders and Voltage- sennsing wire feeders
1/4 inch to 1/2 inch
...

16. List 3 forms compressed gases may be supplied for welding
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
Shielding the molten weld metal from atmospheric contamination
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

17. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
National Electrical Manufactures Association
Flux cored wires
Higher 26 to 35 arc volts
Insufficient current to melt the wire off cleanly

18. What is the effect of too much slope?
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Insufficient current to melt the wire off cleanly
Flux cored wires
85%

19. What is a typical flow rate of CO2 for short circuit transfer?
Short- circuiting transfer - Globular transfer - Spray transfer
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch

20. How many times per second does short circuiting take place?
To prevent drawing of liquid CO2 (Carbon Dioxide)
By there current carrying capacity
Controls the rate of flow of a shielding gas to the gun nozzle
20 to 200 times per second

21. How are GMAW guns rated?
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If you dont know this check your phone
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure

22. Draw a typical volt amp curve for a machine that is designed for GMAW
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone

23. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Puddle fluidity
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

24. Regulators control_____________ flowmeters SHOW____________.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed

25. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
V groove or U groove
3
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

26. What does the wire feeder control?
85%
Guns
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch

27. What type of power source is commonly used with a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone
Constant current (CC)

28. What are the 2 types of wire feeders available?
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders
15 feet (4.5 meters)
Wire feed speed - Voltage control

29. What does inductance control?
The time rate of response for the current rise and fall
15 feet (4.5 meters)
85%
Wire feed speed - Voltage control

30. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)

31. List several industries that would use GMAW
Reducing the gas source pressure to a constant working pressure
When the filler wire is in direct contract with the base metal
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders

32. In the GMAW process what does voltage control?
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Pressure vessels and the piping industry
15 feet (4.5 meters)
The Arc voltage

34. Give a description of 'pinch effect'
Speed of the feed motor and - starting / stopping electrode feed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
15 feet (4.5 meters)
V groove or U groove

35. What type of power source is used with a constant speed wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
Constant voltage (CV)
Wire feed speed

36. What is the purpose of a regulator and what does it indicate on its gauges?
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
Wire feed speed
Reducing the gas source pressure to a constant working pressure

37. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant voltage (CV)

38. What power sources are used with the GMAW Process?
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
...

39. What would be an indication that the drive roll pressure is adjusted correctly?
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%

40. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
If you dont know this check your phone
Constant voltage (CV)
...

41. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc
(DCEP) Direct Current Electrode Positive or Reverse polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas

42. What does the term GMAW identify?
Pressure - The rate of flow of a shielding gas
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gas metal arc welding
Wire feed speed

43. Why is the term GMAW preferred over MIG or MAG?
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
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
These terms are quite restrictive and often technically incorrect

44. What is the required arc voltage used for short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Flux cored wires
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)

45. When is the metal transferred with short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
When the filler wire is in direct contract with the base metal
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association

46. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
V groove or U groove
5.8 to 12.5 L/min
Cause flaking - which can clog the liner and contact tube
3

47. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min
By there current carrying capacity
Gives arc voltage values to the control system of the feeder

48. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity

49. What does a flowmeter do and what does it measure?
The negative side of a welding unit
Constant current (CC)
The time rate of response for the current rise and fall
Controls the rate of flow of a shielding gas to the gun nozzle

50. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
12 to 22 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer