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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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?
SMAW - GTAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate

2. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

3. What is the main purpose of 'slope'?
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
Gas metal arc welding

4. How many times per second does short circuiting take place?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second
1/4 inch to 1/2 inch
Constant current (CC)

5. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
To prevent leakage - Carbon Dioxide (CO2)
Flux cored wires
85%

6. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feed speed - Voltage control
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube
3

7. What controls the wire speed on a voltage sensing wire feeder?
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
National Electrical Manufactures Association

8. Why is a line heater required when using GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
Dry ice can form within the flow control openings and cause blockage of shielding gas
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders

9. What is the required arc voltage used for short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
3
Generally not as accurate
12 to 22 arc volts

10. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Wire feed speed
Shielding the molten weld metal from atmospheric contamination
DCEP (Direct Current Electrode Positive) Reverse Polarity

11. What type of power source is used with a constant speed wire feeder?
The Arc voltage
Constant voltage (CV)
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance

12. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Gives arc voltage values to the control system of the feeder

13. What happens when the electrode extension is increased?
If you dont know this check your phone
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate

14. What 2 organizations designate specifications for GMAW wires?
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
AWS and CSA

15. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Minimum distortion due to low heat input
Wire feed speed - Voltage control
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity

16. What does the wire feeder control?
V groove or U groove
The Arc voltage
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed

17. List 3 forms compressed gases may be supplied for welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Spatter problems and poor weld appearance

18. What is the purpose of a regulator and what does it indicate on its gauges?
Aluminum wire
...
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure

19. What power sources are used with the GMAW Process?
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed

20. What is the maximum distance that hard wire can be successfully pushed?
Constant current (CC)
15 feet (4.5 meters)
SMAW - GTAW
Generally not as accurate

21. What does voltage do in an electrical circuit?
Flux cored wires
Wire feed speed
Voltage is the force that overcomes resistance to allow amperage flow
Shielding the molten weld metal from atmospheric contamination

22. What is the effect of too much slope?
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage

23. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

24. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone

25. Why is a fiber washer required and what cylinder gas requires it?
Constant current (CC)
Higher 26 to 35 arc volts
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW

26. Is the arc voltage for spray transfer higher or lower than that 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
National Electrical Manufactures Association
Higher 26 to 35 arc volts
20 to 200 times per second

27. With straight polarity where is 2/3 of the arc energy?
To limit the short circuiting current so that spatter is reduced
85%
The negative side of a welding unit
V groove or U groove

28. What is a solenoid valve and what actuates it?
Flux cored wires
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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
Aluminum wire

29. What output on the welding machine is used to rate the duty cycle?
Penetration and burn - off rate of the electrode
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

30. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
Wire feed speed

31. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant current (CC)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
National Electrical Manufactures Association

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

33. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
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
If you dont know this check your phone
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gives arc voltage values to the control system of the feeder

34. A pull type drive system is usually used on what type of material?
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant- speed wire feeders and Voltage- sennsing wire feeders

35. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
5.8 to 12.5 L/min
12 to 22 arc volts

36. What processes are constant current (CC) power sources designed to be used with?
When the filler wire is in direct contract with the base metal
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed

37. Regulators control_____________ flowmeters SHOW____________.
Duty cycle
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode
Voltage is the force that overcomes resistance to allow amperage flow

38. What does the abbreviation NEMA stand for?
Minutes of elapsed time continually run (out of 10 minutes)
85%
20 to 200 times per second
National Electrical Manufactures Association

39. How are GMAW guns rated?
85%
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc

40. A 10 minute cycle of welding time vs cooling time a given machine can handle.
(DCEP) Direct Current Electrode Positive or Reverse polarity
Flux cored wires
Duty cycle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

41. Draw a typical volt amp curve for a machine that is designed for GMAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)

42. In the GMAW process what does voltage control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity
Aluminum wire
Voltage is the force that overcomes resistance to allow amperage flow

43. What is the preferred drive roll design for solid wires?
Controls the rate of flow of a shielding gas to the gun nozzle
V groove or U groove
Cause flaking - which can clog the liner and contact tube
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

44. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Constant voltage (CV)
AWS and CSA
Duty cycle

45. What is another term for electrode holders for GMAW?
AWS and CSA
By there current carrying capacity
Guns
Wire feed speed - Voltage control

46. What does the term GMAW identify?
V groove or U groove
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle

47. When is the metal transferred with short circuit transfer?
Duty cycle
Generally not as accurate
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance

48. Give a description of 'pinch effect'
By there current carrying capacity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant voltage (CV)

49. Why is globular transfer generally avoided with GMAW?
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)

50. What type of power source is commonly used with a voltage sensing wire feeder?
When the filler wire is in direct contract with the base metal
Constant current (CC)
15 feet (4.5 meters)
V groove or U groove