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. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube

2. What does the term GMAW identify?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association
Gas metal arc welding

3. What is a solenoid valve and what actuates it?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Wire feed speed - Voltage control
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Duty cycle
The negative side of a welding unit

5. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
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
(DCEP) Direct Current Electrode Positive or Reverse polarity

6. How many times per second does short circuiting take place?
20 to 200 times per second
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
When the filler wire is in direct contract with the base metal

7. What is the recommended electrode stick- out for .035 solid wire?
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch

8. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas
20 to 200 times per second

9. What current and polarity is generally used with GMAW?
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns

10. List 3 forms compressed gases may be supplied for welding
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

11. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)
20 to 200 times per second

12. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The Arc voltage

13. What is the effect of too much slope?
1/4 inch to 1/2 inch
Insufficient current to melt the wire off cleanly
Reducing the gas source pressure to a constant working pressure
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

14. What is the required arc voltage used for short circuit transfer?
AWS and CSA
12 to 22 arc volts
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure

15. What output on the welding machine is used to rate the duty cycle?
Welding process that joins metals by heating them with an electric arc
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minutes of elapsed time continually run (out of 10 minutes)
To prevent leakage - Carbon Dioxide (CO2)

16. What does a flowmeter do and what does it measure?
The Arc voltage
Generally not as accurate
Voltage is the force that overcomes resistance to allow amperage flow
Controls the rate of flow of a shielding gas to the gun nozzle

17. What type of power source is used with a constant speed wire feeder?
If you dont know this check your phone
Constant voltage (CV)
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

18. What controls the wire speed on a voltage sensing wire feeder?
Puddle fluidity
The Arc voltage
Higher 26 to 35 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat

19. What are the 2 types of wire feeders available?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle

20. What happens when the electrode extension is increased?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity
The Arc voltage

21. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Wire feed speed
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
The time rate of response for the current rise and fall

22. What wire are knurled drive rolls most commonly used on?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a shielding gas
The Arc voltage
Flux cored wires

23. What effect does increasing and decreasing the inductance have on the weld?
Gives arc voltage values to the control system of the feeder
Dry ice can form within the flow control openings and cause blockage of shielding gas
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

24. What processes are constant current (CC) power sources designed to be used with?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Cause flaking - which can clog the liner and contact tube
SMAW - GTAW
Voltage is the force that overcomes resistance to allow amperage flow

25. What does inductance control?
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders

26. What controls amperage when using GMAW?
Gives arc voltage values to the control system of the feeder
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed

27. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
When the filler wire is in direct contract with the base metal
Generally not as accurate
...

28. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

29. What type of power source is commonly used with a voltage sensing wire feeder?
Higher 26 to 35 arc volts
Constant current (CC)
To prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow

30. List the three methods of metal transfer with GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer

31. What does the abbreviation NEMA stand for?
Generally not as accurate
National Electrical Manufactures Association
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3

32. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Penetration and burn - off rate of the electrode
Minimum distortion due to low heat input
Constant current (CC)

33. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow

34. Give a brief description of the GMAW process
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Welding process that joins metals by heating them with an electric arc

35. List the basic equipment requirements for the GMAW process
Flux cored wires
85%
When the filler wire is in direct contract with the base metal
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
85%
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

37. Regulators control_____________ flowmeters SHOW____________.
Reducing the gas source pressure to a constant working pressure
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
Pressure - The rate of flow of a shielding gas

38. What is the purpose of a regulator and what does it indicate on its gauges?
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Reducing the gas source pressure to a constant working pressure

39. List several industries that would use GMAW
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc
Pressure vessels and the piping industry
V groove or U groove

40. List 3 wire drive systems and give a short description of each
15 feet (4.5 meters)
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
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)

41. What does voltage do in an electrical circuit?
Spatter problems and poor weld appearance
SMAW - GTAW
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow

42. How are GMAW guns rated?
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
By there current carrying capacity

43. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
Wire feeds smoothly (yet will slip should a problem occur in the gun)

44. Why is a line heater required when using GMAW?
The time rate of response for the current rise and fall
Dry ice can form within the flow control openings and cause blockage of shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity

45. A pull type drive system is usually used on what type of material?
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Aluminum wire
Shielding the molten weld metal from atmospheric contamination

46. Draw a typical volt amp curve for a machine that is designed for GMAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
National Electrical Manufactures Association
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow

47. Give a description of 'pinch effect'
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
AWS and CSA
Dry ice can form within the flow control openings and cause blockage of shielding gas

48. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Motor driven generators - Transformer rectifiers - and Inverter designs
When the filler wire is in direct contract with the base metal
3
Generally not as accurate

49. Why is the term GMAW preferred over MIG or MAG?
The time rate of response for the current rise and fall
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect

50. What is an advantage of pulsed arc transfer with GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system