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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. When is the metal transferred with short circuit transfer?
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination
When the filler wire is in direct contract with the base metal

2. What does inductance control?
15 feet (4.5 meters)
The time rate of response for the current rise and fall
The resistace to electrical current flow increases with it. Causing the electrode to heat
Short- circuiting transfer - Globular transfer - Spray transfer

3. List the factors that determine the mode of metal transfer
Higher 26 to 35 arc volts
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Motor driven generators - Transformer rectifiers - and Inverter designs

4. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Duty cycle
Generally not as accurate
3
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. What is the effect of too much slope?
The Arc voltage
Dry ice can form within the flow control openings and cause blockage of shielding gas
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed

6. What happens when the electrode extension is increased?
Insufficient current to melt the wire off cleanly
Duty cycle
The resistace to electrical current flow increases with it. Causing the electrode to heat
These terms are quite restrictive and often technically incorrect

7. What does the term GMAW identify?
Aluminum wire
85%
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding

8. Why is a fiber washer required and what cylinder gas requires it?
The resistace to electrical current flow increases with it. Causing the electrode to heat
National Electrical Manufactures Association
To prevent leakage - Carbon Dioxide (CO2)
Motor driven generators - Transformer rectifiers - and Inverter designs

9. What is the key advantage of short circuiting transfer?
Wire feed speed
Minimum distortion due to low heat input
Higher 26 to 35 arc volts
Gas metal arc welding

10. What is the disadvantage of the gauge preset type of regulator/flowmeter?
15 feet (4.5 meters)
Generally not as accurate
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
Guns

11. What does the wire feeder control?
Reducing the gas source pressure to a constant working pressure
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed
AWS and CSA

12. Regulators control_____________ flowmeters SHOW____________.
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
National Electrical Manufactures Association

13. Draw a typical volt amp curve for a machine that is designed for GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone

14. What is a solenoid valve and what actuates it?
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure - The rate of flow of a shielding gas

15. What controls amperage when using GMAW?
Wire feed speed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
AWS and CSA
The negative side of a welding unit

16. List several industries that would use GMAW
5.8 to 12.5 L/min
Spatter problems and poor weld appearance
Pressure vessels and the piping industry
Controls the rate of flow of a shielding gas to the gun nozzle

17. What does the abbreviation NEMA stand for?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed - Voltage control
The Arc voltage
National Electrical Manufactures Association

18. What is the preferred drive roll design for solid wires?
V groove or U groove
1/4 inch to 1/2 inch
Short- circuiting transfer - Globular transfer - Spray transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

19. A pull type drive system is usually used on what type of material?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Aluminum wire
85%
Constant current (CC)

20. What are the 2 types of wire feeders available?
When the filler wire is in direct contract with the base metal
Flux cored wires
Constant- speed wire feeders and Voltage- sennsing wire feeders
...

21. 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
Higher 26 to 35 arc volts
V groove or U groove
SMAW - GTAW

22. What controls the wire speed on a voltage sensing wire feeder?
V groove or U groove
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage
5.8 to 12.5 L/min

23. What would be an indication that the drive roll pressure is adjusted correctly?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
National Electrical Manufactures Association

24. What does voltage do in an electrical circuit?
12 to 22 arc volts
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control

25. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The negative side of a welding unit

26. What power sources are used with the GMAW Process?
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)

27. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
1/4 inch to 1/2 inch
Shielding the molten weld metal from atmospheric contamination

28. How many times per second does short circuiting take place?
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

29. What processes are constant current (CC) power sources designed to be used with?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
SMAW - GTAW
Higher 26 to 35 arc volts
Puddle fluidity

30. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Controls the rate of flow of a shielding gas to the gun nozzle

31. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gives arc voltage values to the control system of the feeder
Constant voltage (CV)
1/4 inch to 1/2 inch

32. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)

33. How are GMAW guns rated?
By there current carrying capacity
Gives arc voltage values to the control system of the feeder
3
1/4 inch to 1/2 inch

34. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
...
20 to 200 times per second

35. What current and polarity is generally used with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
Pressure - The rate of flow of a shielding gas
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. List 3 wire drive systems and give a short description of each
Duty cycle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
1/4 inch to 1/2 inch
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

37. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
These terms are quite restrictive and often technically incorrect
12 to 22 arc volts
If you dont know this check your phone

38. What is the required arc voltage used for short circuit transfer?
Penetration and burn - off rate of the electrode
12 to 22 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas

39. What is an advantage of pulsed arc transfer with GMAW?
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
SMAW - GTAW
If you dont know this check your phone

40. What is the purpose of a regulator and what does it indicate on its gauges?
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Constant current (CC)
Insufficient current to melt the wire off cleanly
Dry ice can form within the flow control openings and cause blockage of shielding gas

42. List the basic equipment requirements for the GMAW process
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

43. What is another term for electrode holders for GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding process that joins metals by heating them with an electric arc
Minimum distortion due to low heat input
Guns

44. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
DCEP (Direct Current Electrode Positive) Reverse Polarity

45. List 3 forms compressed gases may be supplied for welding
Short- circuiting transfer - Globular transfer - Spray transfer
12 to 22 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination

46. What 2 organizations designate specifications for GMAW wires?
The negative side of a welding unit
AWS and CSA
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas

47. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow

48. What is the recommended electrode stick- out for .035 solid wire?
Minimum distortion due to low heat input
Wire feed speed
1/4 inch to 1/2 inch
Short- circuiting transfer - Globular transfer - Spray transfer

49. List the three methods of metal transfer with GMAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
Controls the rate of flow of a shielding gas to the gun nozzle
Short- circuiting transfer - Globular transfer - Spray transfer

50. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
(DCEP) Direct Current Electrode Positive or Reverse polarity