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Test your basic knowledge |

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. Give a description of 'pinch effect'
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

2. How many times per second does short circuiting take place?
3
Cause flaking - which can clog the liner and contact tube
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second

3. What does the wire feeder control?
Shielding the molten weld metal from atmospheric contamination
12 to 22 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed

4. What 2 organizations designate specifications for GMAW wires?
By there current carrying capacity
Pressure vessels and the piping industry
Guns
AWS and CSA

5. What is an advantage of pulsed arc transfer with GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity

6. What wire are knurled drive rolls most commonly used on?
Generally not as accurate
These terms are quite restrictive and often technically incorrect
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Duty cycle
...
Cause flaking - which can clog the liner and contact tube
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

8. Why is a fiber washer required and what cylinder gas requires it?
Puddle fluidity
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent leakage - Carbon Dioxide (CO2)

9. List 3 wire drive systems and give a short description of each
Speed of the feed motor and - starting / stopping electrode feed
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
By there current carrying capacity

10. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The time rate of response for the current rise and fall
Gives arc voltage values to the control system of the feeder

11. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat

12. Give a brief description of the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
20 to 200 times per second
Welding process that joins metals by heating them with an electric arc
To prevent drawing of liquid CO2 (Carbon Dioxide)

13. List the factors that determine the mode of metal transfer
12 to 22 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

14. What is the main purpose of 'slope'?
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)

15. In the GMAW process what does voltage control?
Constant voltage (CV)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
15 feet (4.5 meters)
Puddle fluidity

16. What is the key advantage of short circuiting transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minimum distortion due to low heat input
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode

17. Why is the term GMAW preferred over MIG or MAG?
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed
These terms are quite restrictive and often technically incorrect
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

18. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
20 to 200 times per second
Wire feed speed

19. What is a typical flow rate of CO2 for short circuit transfer?
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
5.8 to 12.5 L/min
1/4 inch to 1/2 inch

20. What is another term for electrode holders for GMAW?
Guns
Aluminum wire
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
...

21. What controls amperage when using GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure vessels and the piping industry
Wire feed speed
Insufficient current to melt the wire off cleanly

22. List the three methods of metal transfer with GMAW
When the filler wire is in direct contract with the base metal
3
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly

23. Regulators control_____________ flowmeters SHOW____________.
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)

24. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
V groove or U groove
3
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed - Voltage control

25. What current and polarity is generally used with GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity

26. What is the preferred drive roll design for solid wires?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...
V groove or U groove
Constant current (CC)

27. What does a flowmeter do and what does it measure?
Constant current (CC)
1/4 inch to 1/2 inch
Wire feed speed
Controls the rate of flow of a shielding gas to the gun nozzle

28. Why is a line heater required when using GMAW?
If you dont know this check your phone
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas
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

29. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
1/4 inch to 1/2 inch
85%
Shielding the molten weld metal from atmospheric contamination
Gas metal arc welding

30. How are GMAW guns rated?
Short- circuiting transfer - Globular transfer - Spray transfer
By there current carrying capacity
Guns
SMAW - GTAW

31. What happens when the electrode extension is increased?
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
The resistace to electrical current flow increases with it. Causing the electrode to heat
When the filler wire is in direct contract with the base metal

32. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Voltage is the force that overcomes resistance to allow amperage flow
Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)

33. What type of power source is used with a constant speed wire feeder?
Puddle fluidity
AWS and CSA
Constant voltage (CV)
If you dont know this check your phone

34. What does voltage do in an electrical circuit?
To prevent drawing of liquid CO2 (Carbon Dioxide)
The Arc voltage
National Electrical Manufactures Association
Voltage is the force that overcomes resistance to allow amperage flow

35. What is the purpose of a regulator and what does it indicate on its gauges?
Constant voltage (CV)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant- speed wire feeders and Voltage- sennsing wire feeders
Reducing the gas source pressure to a constant working pressure

36. A 10 minute cycle of welding time vs cooling time a given machine can handle.
National Electrical Manufactures Association
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding process that joins metals by heating them with an electric arc
Duty cycle

37. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
V groove or U groove
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone
20 to 200 times per second

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
Minutes of elapsed time continually run (out of 10 minutes)
Reducing the gas source pressure to a constant working pressure

39. What is the disadvantage of the gauge preset type of regulator/flowmeter?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate
20 to 200 times per second
If you dont know this check your phone

40. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)

41. What effect does increasing and decreasing the inductance have on the weld?
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
Constant current (CC)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

42. List 3 forms compressed gases may be supplied for welding
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)

43. What 2 controls are found on a GMAW set- up?
Generally not as accurate
Guns
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed - Voltage control

44. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed
Higher 26 to 35 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity

45. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Reducing the gas source pressure to a constant working pressure
Short- circuiting transfer - Globular transfer - Spray transfer
Spatter problems and poor weld appearance
Cause flaking - which can clog the liner and contact tube

46. What is the required arc voltage used for short circuit transfer?
Constant current (CC)
12 to 22 arc volts
Minimum distortion due to low heat input
When the filler wire is in direct contract with the base metal

47. What is the maximum distance that hard wire can be successfully pushed?
If you dont know this check your phone
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
15 feet (4.5 meters)

48. List the basic equipment requirements for the GMAW process
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association

49. In the GMAW process what does amperage control?
20 to 200 times per second
Generally not as accurate
AWS and CSA
Penetration and burn - off rate of the electrode

50. What does the term GMAW identify?
Generally not as accurate
Minutes of elapsed time continually run (out of 10 minutes)
The negative side of a welding unit
Gas metal arc welding