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. What does inductance control?
20 to 200 times per second
The time rate of response for the current rise and fall
Insufficient current to melt the wire off cleanly
Flux cored wires

2. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
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
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal

3. In the GMAW process what does voltage control?
Puddle fluidity
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
5.8 to 12.5 L/min
National Electrical Manufactures Association

4. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
85%
Constant voltage (CV)

5. What does the term GMAW identify?
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires
Gas metal arc welding
National Electrical Manufactures Association

6. List 3 wire drive systems and give a short description of each
Gives arc voltage values to the control system of the feeder
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
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders

7. What happens when the electrode extension is increased?
AWS and CSA
National Electrical Manufactures Association
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant- speed wire feeders and Voltage- sennsing wire feeders

8. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube

9. Give a description of 'pinch effect'
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Penetration and burn - off rate of the electrode
(DCEP) Direct Current Electrode Positive or Reverse polarity

10. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Puddle fluidity
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder

11. What is the purpose of the shielding gas used in GMAW?
To limit the short circuiting current so that spatter is reduced
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity

12. What is another term for electrode holders for GMAW?
Guns
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer
3

13. When is the metal transferred with short circuit transfer?
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal

14. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Pressure - The rate of flow of a shielding gas
Puddle fluidity
If you dont know this check your phone

15. What are the 2 types of wire feeders available?
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)

16. What is the maximum distance that hard wire can be successfully pushed?
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure
15 feet (4.5 meters)

17. What is the effect of too much slope?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Insufficient current to melt the wire off cleanly
Duty cycle
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

18. What does the abbreviation NEMA stand for?
Minutes of elapsed time continually run (out of 10 minutes)
National Electrical Manufactures Association
Reducing the gas source pressure to a constant working pressure
Penetration and burn - off rate of the electrode

19. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gives arc voltage values to the control system of the feeder
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Generally not as accurate

20. Why is a line heater required when using GMAW?
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle

21. What controls the wire speed on a voltage sensing wire feeder?
Pressure vessels and the piping industry
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage

22. What is the required arc voltage used for short circuit transfer?
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Motor driven generators - Transformer rectifiers - and Inverter designs
12 to 22 arc volts

23. With straight polarity where is 2/3 of the arc energy?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit
SMAW - GTAW

24. What is an advantage of pulsed arc transfer with GMAW?
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

25. What is the main purpose of 'slope'?
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed

26. What 2 organizations designate specifications for GMAW wires?
Pressure - The rate of flow of a shielding gas
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity

27. What is the purpose of a regulator and what does it indicate on its gauges?
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
National Electrical Manufactures Association
Reducing the gas source pressure to a constant working pressure

28. List the factors that determine the mode of metal transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
12 to 22 arc volts
To limit the short circuiting current so that spatter is reduced

29. What effect does increasing and decreasing the inductance have on the weld?
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
These terms are quite restrictive and often technically incorrect

30. What is a solenoid valve and what actuates it?
Controls the rate of flow of a shielding gas to the gun nozzle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gives arc voltage values to the control system of the feeder

31. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Shielding the molten weld metal from atmospheric contamination
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Generally not as accurate

32. What controls amperage when using GMAW?
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed

33. Why must CO2 cylinders be used in the vertical position?
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas

34. Why is a fiber washer required and what cylinder gas requires it?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder

35. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
Flux cored wires

36. What is the recommended electrode stick- out for .035 solid wire?
Duty cycle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
If you dont know this check your phone

37. How are GMAW guns rated?
The time rate of response for the current rise and fall
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Higher 26 to 35 arc volts

38. Regulators control_____________ flowmeters SHOW____________.
Flux cored wires
Constant current (CC)
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly

39. In the GMAW process what does amperage control?
5.8 to 12.5 L/min
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode
The Arc voltage

40. A pull type drive system is usually used on what type of material?
Aluminum wire
Insufficient current to melt the wire off cleanly
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced

41. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
The negative side of a welding unit
Welding process that joins metals by heating them with an electric arc
20 to 200 times per second
...

42. What output on the welding machine is used to rate the duty cycle?
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
5.8 to 12.5 L/min
Higher 26 to 35 arc volts

43. List the three methods of metal transfer with GMAW
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW
Generally not as accurate

44. What type of power source is commonly used with a voltage sensing wire feeder?
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)
To prevent leakage - Carbon Dioxide (CO2)
Constant current (CC)

45. What 2 controls are found on a GMAW set- up?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed - Voltage control
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle

46. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Short- circuiting transfer - Globular transfer - Spray transfer

47. What does the wire feeder control?
Voltage is the force that overcomes resistance to allow amperage flow
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
These terms are quite restrictive and often technically incorrect

48. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Wire feed speed
3
12 to 22 arc volts
15 feet (4.5 meters)

49. List 3 forms compressed gases may be supplied for welding
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The time rate of response for the current rise and fall

50. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
When the filler wire is in direct contract with the base metal
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%