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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 would be an indication that the drive roll pressure is adjusted correctly?
Pressure vessels and the piping industry
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

2. Why is a fiber washer required and what cylinder gas requires it?
Cause flaking - which can clog the liner and contact tube
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)
Constant- speed wire feeders and Voltage- sennsing wire feeders

3. What is the effect of too much slope?
Shielding the molten weld metal from atmospheric contamination
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode

4. 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
By there current carrying capacity
...

5. How are GMAW guns rated?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
85%
By there current carrying capacity
These terms are quite restrictive and often technically incorrect

6. What is the key advantage of short circuiting transfer?
If you dont know this check your phone
Minimum distortion due to low heat input
Guns
Shielding the molten weld metal from atmospheric contamination

7. What wire are knurled drive rolls most commonly used on?
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires
Minimum distortion due to low heat input
Constant voltage (CV)

8. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
Speed of the feed motor and - starting / stopping electrode feed
Voltage is the force that overcomes resistance to allow amperage flow

9. A pull type drive system is usually used on what type of material?
Aluminum wire
The time rate of response for the current rise and fall
Minimum distortion due to low heat input
1/4 inch to 1/2 inch

10. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
Short- circuiting transfer - Globular transfer - Spray transfer

11. List the basic equipment requirements for the GMAW process
Gas metal arc welding
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input

12. What does the term GMAW identify?
Aluminum wire
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding
National Electrical Manufactures Association

13. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove
3
To limit the short circuiting current so that spatter is reduced

14. List the factors that determine the mode of metal transfer
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
SMAW - GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

15. What does the wire feeder control?
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity

16. What is the required arc voltage used for short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
12 to 22 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle

17. In the GMAW process what does voltage control?
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed

18. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination

19. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Welding process that joins metals by heating them with an electric arc
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

20. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)
Insufficient current to melt the wire off cleanly

21. Draw a typical volt amp curve for a machine that is designed for GMAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Cause flaking - which can clog the liner and contact tube
AWS and CSA
If you dont know this check your phone

22. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Spatter problems and poor weld appearance
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders

23. How many times per second does short circuiting take place?
3
The time rate of response for the current rise and fall
20 to 200 times per second
If you dont know this check your phone

24. What is an advantage of pulsed arc transfer with GMAW?
The time rate of response for the current rise and fall
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs

25. What output on the welding machine is used to rate the duty cycle?
Wire feed speed
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect
Minutes of elapsed time continually run (out of 10 minutes)

26. What type of power source is used with a constant speed wire feeder?
...
Constant voltage (CV)
AWS and CSA
Constant current (CC)

27. What is the purpose of the shielding gas used in GMAW?
Guns
By there current carrying capacity
...
Shielding the molten weld metal from atmospheric contamination

28. Why is a line heater required when using GMAW?
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant current (CC)
Puddle fluidity

29. Regulators control_____________ flowmeters SHOW____________.
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
The negative side of a welding unit
Pressure - The rate of flow of a shielding gas

30. What processes are constant current (CC) power sources designed to be used with?
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW
Gives arc voltage values to the control system of the feeder
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

31. What are the 2 types of wire feeders available?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second
Constant current (CC)

32. What does the abbreviation NEMA stand for?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant voltage (CV)

33. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Aluminum wire

34. What power sources are used with the GMAW Process?
3
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

35. What 2 organizations designate specifications for GMAW wires?
...
AWS and CSA
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)

36. What is the main purpose of 'slope'?
Gives arc voltage values to the control system of the feeder
The time rate of response for the current rise and fall
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow

37. What type of power source is commonly used with a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Constant current (CC)
Generally not as accurate
The time rate of response for the current rise and fall

38. Give a description of 'pinch effect'
Dry ice can form within the flow control openings and cause blockage of shielding gas
...
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
AWS and CSA

39. With straight polarity where is 2/3 of the arc energy?
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min
The negative side of a welding unit

40. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
85%
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer

41. Give a brief description of the GMAW process
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
85%
Welding process that joins metals by heating them with an electric arc

42. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Minimum distortion due to low heat input
If you dont know this check your phone
Speed of the feed motor and - starting / stopping electrode feed

43. What does inductance control?
Penetration and burn - off rate of the electrode
The time rate of response for the current rise and fall
To limit the short circuiting current so that spatter is reduced
The Arc voltage

44. What controls the wire speed on a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
12 to 22 arc volts
If you dont know this check your phone
The Arc voltage

45. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
Flux cored wires

46. When is the metal transferred with short circuit transfer?
20 to 200 times per second
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association

47. What current and polarity is generally used with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry
DCEP (Direct Current Electrode Positive) Reverse Polarity

48. List 3 wire drive systems and give a short description of each
Constant current (CC)
If you dont know this check your phone
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
Cause flaking - which can clog the liner and contact tube

49. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
...
Short- circuiting transfer - Globular transfer - Spray transfer

50. What is another term for electrode holders for GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
3
Wire feed speed - Voltage control
Guns