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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. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
Cause flaking - which can clog the liner and contact tube
Flux cored wires

2. A pull type drive system is usually used on what type of material?
Wire feed speed - Voltage control
National Electrical Manufactures Association
Aluminum wire
Minimum distortion due to low heat input

3. What is the recommended electrode stick- out for .035 solid wire?
85%
Pressure vessels and the piping industry
SMAW - GTAW
1/4 inch to 1/2 inch

4. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
85%
Wire feed speed - Voltage control
3
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. What does the abbreviation NEMA stand for?
Wire feed speed - Voltage control
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
National Electrical Manufactures Association

6. What 2 controls are found on a GMAW set- up?
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

7. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity
Insufficient current to melt the wire off cleanly
Welding process that joins metals by heating them with an electric arc

8. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gives arc voltage values to the control system of the feeder

9. 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
These terms are quite restrictive and often technically incorrect
Puddle fluidity
Flux cored wires

10. Draw a typical volt amp curve for a machine that is designed for GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)
If you dont know this check your phone

11. List 3 wire drive systems and give a short description of each
5.8 to 12.5 L/min
By there current carrying capacity
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

12. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
5.8 to 12.5 L/min
Minimum distortion due to low heat input
AWS and CSA

13. What would be an indication that the drive roll pressure is adjusted correctly?
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

14. Why is a line heater required when using GMAW?
Minimum distortion due to low heat input
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
The Arc voltage

15. Regulators control_____________ flowmeters SHOW____________.
Flux cored wires
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

16. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)
National Electrical Manufactures Association

17. List 3 forms compressed gases may be supplied for welding
Spatter problems and poor weld appearance
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

18. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Guns
Reducing the gas source pressure to a constant working pressure
The resistace to electrical current flow increases with it. Causing the electrode to heat

19. Why is the term GMAW preferred over MIG or MAG?
AWS and CSA
Guns
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect

20. What is the purpose of the shielding gas used in GMAW?
AWS and CSA
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association

21. What 2 organizations designate specifications for GMAW wires?
Flux cored wires
AWS and CSA
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

22. What is a solenoid valve and what actuates it?
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle
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

23. List the factors that determine the mode of metal transfer
12 to 22 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant current (CC)

24. What wire are knurled drive rolls most commonly used on?
Constant current (CC)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires
Shielding the molten weld metal from atmospheric contamination

25. What output on the welding machine is used to rate the duty cycle?
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feeds smoothly (yet will slip should a problem occur in the gun)

26. In the GMAW process what does voltage control?
Insufficient current to melt the wire off cleanly
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) Reverse Polarity
Puddle fluidity

27. What is the key advantage of short circuiting transfer?
Gas metal arc welding
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minimum distortion due to low heat input
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

28. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Aluminum wire
85%
Guns
15 feet (4.5 meters)

29. Give a description of 'pinch effect'
Constant current (CC)
Higher 26 to 35 arc volts
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

30. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Constant voltage (CV)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle

31. How are GMAW guns rated?
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs

32. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
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
Shielding the molten weld metal from atmospheric contamination

33. What current and polarity is generally used with GMAW?
The time rate of response for the current rise and fall
Short- circuiting transfer - Globular transfer - Spray transfer
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity

34. What does inductance control?
If you dont know this check your phone
The time rate of response for the current rise and fall
National Electrical Manufactures Association
Pressure vessels and the piping industry

35. What processes are constant current (CC) power sources designed to be used with?
Pressure - The rate of flow of a shielding gas
SMAW - GTAW
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed

36. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
...
The resistace to electrical current flow increases with it. Causing the electrode to heat

37. What controls the wire speed on a voltage sensing wire feeder?
Minimum distortion due to low heat input
The Arc voltage
The resistace to electrical current flow increases with it. Causing the electrode to heat
15 feet (4.5 meters)

38. Why is a fiber washer required and what cylinder gas requires it?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode

39. What happens when the electrode extension is increased?
National Electrical Manufactures Association
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate
Aluminum wire

40. What does the wire feeder control?
Flux cored wires
...
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure

41. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
Puddle fluidity
Constant voltage (CV)

42. What is the main purpose of 'slope'?
1/4 inch to 1/2 inch
The resistace to electrical current flow increases with it. Causing the electrode to heat
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced

43. Give a brief description of the GMAW process
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle

44. What are the 2 types of wire feeders available?
20 to 200 times per second
Aluminum wire
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination

45. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
15 feet (4.5 meters)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feeds smoothly (yet will slip should a problem occur in the gun)

46. What does voltage do in an electrical circuit?
Spatter problems and poor weld appearance
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow
Aluminum wire

47. What power sources are used with the GMAW Process?
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas

48. List several industries that would use GMAW
Minimum distortion due to low heat input
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)
Motor driven generators - Transformer rectifiers - and Inverter designs

49. What does a flowmeter do and what does it measure?
Constant current (CC)
Wire feed speed - Voltage control
Controls the rate of flow of a shielding gas to the gun nozzle
Higher 26 to 35 arc volts

50. Why is globular transfer generally avoided with GMAW?
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance
Aluminum wire