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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. List 3 forms compressed gases may be supplied for welding
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Flux cored wires
Wire feed speed

2. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
National Electrical Manufactures Association
3
Wire feed speed

3. Regulators control_____________ flowmeters SHOW____________.
Spatter problems and poor weld appearance
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas

4. What does voltage do in an electrical circuit?
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To limit the short circuiting current so that spatter is reduced
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
When the filler wire is in direct contract with the base metal

6. What are the 2 types of wire feeders available?
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
Constant- speed wire feeders and Voltage- sennsing wire feeders

7. What is the purpose of a regulator and what does it indicate on its gauges?
Higher 26 to 35 arc volts
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
To limit the short circuiting current so that spatter is reduced

8. What is the purpose of the shielding gas used in GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly

9. List the basic equipment requirements for the GMAW process
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To limit the short circuiting current so that spatter is reduced
SMAW - GTAW

10. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Minimum distortion due to low heat input
Penetration and burn - off rate of the electrode
Duty cycle

11. What is the preferred drive roll design for solid wires?
Constant voltage (CV)
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The Arc voltage

12. What 2 organizations designate specifications for GMAW wires?
Constant current (CC)
AWS and CSA
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow

13. What is a typical flow rate of CO2 for short circuit transfer?
Gives arc voltage values to the control system of the feeder
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
5.8 to 12.5 L/min
Constant voltage (CV)

14. 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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3

15. In the GMAW process what does voltage control?
Puddle fluidity
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode

16. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
If you dont know this check your phone
...
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders

17. What is the key advantage of short circuiting transfer?
AWS and CSA
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input

18. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
SMAW - GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal

19. What current and polarity is generally used with GMAW?
Puddle fluidity
Pressure - The rate of flow of a shielding gas
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage

20. What 2 controls are found on a GMAW set- up?
Short- circuiting transfer - Globular transfer - Spray transfer
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect

21. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity
Puddle fluidity
Constant voltage (CV)

22. What is the main purpose of 'slope'?
Wire feed speed
Flux cored wires
Spatter problems and poor weld appearance
To limit the short circuiting current so that spatter is reduced

23. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry

24. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
Spatter problems and poor weld appearance
Aluminum wire

25. What type of power source is commonly used with a voltage sensing wire feeder?
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Constant current (CC)

26. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
3

27. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
15 feet (4.5 meters)

28. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Wire feed speed - Voltage control
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)

29. What processes are constant current (CC) power sources designed to be used with?
Minutes of elapsed time continually run (out of 10 minutes)
To limit the short circuiting current so that spatter is reduced
Duty cycle
SMAW - GTAW

30. What effect does increasing and decreasing the inductance have on the weld?
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Insufficient current to melt the wire off cleanly
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

31. How many times per second does short circuiting take place?
These terms are quite restrictive and often technically incorrect
20 to 200 times per second
12 to 22 arc volts
Insufficient current to melt the wire off cleanly

32. What happens when the electrode extension is increased?
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
The resistace to electrical current flow increases with it. Causing the electrode to heat

33. Why is a line heater required when using GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed - Voltage control

34. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
85%
3
...
DCEP (Direct Current Electrode Positive) Reverse Polarity

35. What is the required arc voltage used for short circuit transfer?
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed

36. What does a flowmeter do and what does it measure?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent drawing of liquid CO2 (Carbon Dioxide)

37. List 3 wire drive systems and give a short description of each
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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
Penetration and burn - off rate of the electrode

38. What is a solenoid valve and what actuates it?
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal

39. What is the maximum distance that hard wire can be successfully pushed?
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)

40. List several industries that would use GMAW
The time rate of response for the current rise and fall
If you dont know this check your phone
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. Why must CO2 cylinders be used in the vertical position?
Wire feed speed - Voltage control
To prevent leakage - Carbon Dioxide (CO2)
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)

42. What does inductance control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
12 to 22 arc volts

43. In the GMAW process what does amperage control?
Gives arc voltage values to the control system of the feeder
Penetration and burn - off rate of the electrode
Constant current (CC)
Guns

44. Draw a typical volt amp curve for a machine that is designed for GMAW
Puddle fluidity
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed
If you dont know this check your phone

45. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)
Constant current (CC)

46. What is an advantage of pulsed arc transfer with GMAW?
Constant current (CC)
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
Wire feed speed

47. A 10 minute cycle of welding time vs cooling time a given machine can handle.
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
Duty cycle
Speed of the feed motor and - starting / stopping electrode feed

48. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Constant- speed wire feeders and Voltage- sennsing wire feeders
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas

49. What is another term for electrode holders for GMAW?
Guns
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity
3

50. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
V groove or U groove
1/4 inch to 1/2 inch