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. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
To limit the short circuiting current so that spatter is reduced

2. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
85%

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
Gives arc voltage values to the control system of the feeder
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

4. What is the required arc voltage used for short circuit transfer?
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires
12 to 22 arc volts

5. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)

6. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Shielding the molten weld metal from atmospheric contamination
Higher 26 to 35 arc volts
Guns
Insufficient current to melt the wire off cleanly

7. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
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
If you dont know this check your phone

8. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Cause flaking - which can clog the liner and contact tube
Wire feeds smoothly (yet will slip should a problem occur in the gun)

9. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts

10. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Higher 26 to 35 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)

11. Why must CO2 cylinders be used in the vertical position?
Gas metal arc welding
The negative side of a welding unit
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. What is the effect of too much slope?
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow

13. How many times per second does short circuiting take place?
1/4 inch to 1/2 inch
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

14. What wire are knurled drive rolls most commonly used on?
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
Flux cored wires
Spatter problems and poor weld appearance

15. What is a solenoid valve and what actuates it?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Aluminum wire
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Higher 26 to 35 arc volts

16. List several industries that would use GMAW
Insufficient current to melt the wire off cleanly
Pressure vessels and the piping industry
Flux cored wires
3

17. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
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
The negative side of a welding unit

18. A pull type drive system is usually used on what type of material?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Aluminum wire
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)

19. With straight polarity where is 2/3 of the arc energy?
Duty cycle
The negative side of a welding unit
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)

20. What is an advantage of pulsed arc transfer with GMAW?
Welding process that joins metals by heating them with an electric arc
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Flux cored wires
Wire feeds smoothly (yet will slip should a problem occur in the gun)

21. In the GMAW process what does voltage control?
Puddle fluidity
Gives arc voltage values to the control system of the feeder
Controls the rate of flow of a shielding gas to the gun nozzle
Shielding the molten weld metal from atmospheric contamination

22. What happens when the electrode extension is increased?
(DCEP) Direct Current Electrode Positive or Reverse polarity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry

23. What does the abbreviation NEMA stand for?
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association

24. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
3
1/4 inch to 1/2 inch

25. What does a flowmeter do and what does it measure?
Gives arc voltage values to the control system of the feeder
Puddle fluidity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Controls the rate of flow of a shielding gas to the gun nozzle

26. How are GMAW guns rated?
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

27. Why is globular transfer generally avoided with GMAW?
Pressure vessels and the piping industry
Spatter problems and poor weld appearance
Cause flaking - which can clog the liner and contact tube
To limit the short circuiting current so that spatter is reduced

28. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure - The rate of flow of a shielding gas
Aluminum wire
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

29. What processes are constant current (CC) power sources designed to be used with?
To limit the short circuiting current so that spatter is reduced
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW

30. What is the preferred drive roll design for solid wires?
Wire feed speed - Voltage control
V groove or U groove
Flux cored wires
National Electrical Manufactures Association

31. List 3 wire drive systems and give a short description of each
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 feed speed - Voltage control
If you dont know this check your phone

32. What is a typical flow rate of CO2 for short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed

33. What is the main purpose of 'slope'?
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed - Voltage control

34. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Shielding the molten weld metal from atmospheric contamination

35. What current and polarity is generally used with GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow
Wire feeds smoothly (yet will slip should a problem occur in the gun)
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What controls amperage when using GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association

37. What would be an indication that the drive roll pressure is adjusted correctly?
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed
3

38. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
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
By there current carrying capacity

39. What does the term GMAW identify?
SMAW - GTAW
AWS and CSA
Gas metal arc welding
Wire feed speed - Voltage control

40. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity

41. What is the key advantage of short circuiting transfer?
Constant voltage (CV)
Wire feed speed
Minimum distortion due to low heat input
Controls the rate of flow of a shielding gas to the gun nozzle

42. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Constant- speed wire feeders and Voltage- sennsing wire feeders
1/4 inch to 1/2 inch
Constant voltage (CV)

43. A 10 minute cycle of welding time vs cooling time a given machine can handle.
These terms are quite restrictive and often technically incorrect
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
15 feet (4.5 meters)

44. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
Dry ice can form within the flow control openings and cause blockage of shielding gas

45. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
To prevent leakage - Carbon Dioxide (CO2)
Puddle fluidity
If you dont know this check your phone

46. What output on the welding machine is used to rate the duty cycle?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
Duty cycle
By there current carrying capacity

47. What is the recommended electrode stick- out for .035 solid wire?
These terms are quite restrictive and often technically incorrect
20 to 200 times per second
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

48. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
National Electrical Manufactures Association
If you dont know this check your phone
...
Higher 26 to 35 arc volts

49. What power sources are used with the GMAW Process?
If you dont know this check your phone
...
15 feet (4.5 meters)
Motor driven generators - Transformer rectifiers - and Inverter designs

50. What is the maximum distance that hard wire can be successfully pushed?
Guns
15 feet (4.5 meters)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)