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. List 3 forms compressed gases may be supplied for welding
AWS and CSA
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding

2. What is a solenoid valve and what actuates it?
Controls the rate of flow of a shielding gas to the gun nozzle
Guns
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Spatter problems and poor weld appearance

3. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Guns
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts

4. What is another term for electrode holders for GMAW?
Welding process that joins metals by heating them with an electric arc
The time rate of response for the current rise and fall
Guns
Constant current (CC)

5. What 2 organizations designate specifications for GMAW wires?
National Electrical Manufactures Association
AWS and CSA
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

6. A pull type drive system is usually used on what type of material?
When the filler wire is in direct contract with the base metal
...
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Aluminum wire

7. How many times per second does short circuiting take place?
20 to 200 times per second
V groove or U groove
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer

8. What output on the welding machine is used to rate the duty cycle?
Generally not as accurate
85%
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)

9. What type of power source is commonly used with a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
Constant current (CC)
SMAW - GTAW
Flux cored wires

10. What does the abbreviation NEMA stand for?
The time rate of response for the current rise and fall
National Electrical Manufactures Association
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)

11. Why is a fiber washer required and what cylinder gas requires it?
Pressure vessels and the piping industry
Gas metal arc welding
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)

12. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts

13. What wire are knurled drive rolls most commonly used on?
Pressure vessels and the piping industry
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
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 a typical flow rate of CO2 for short circuit transfer?
The Arc voltage
1/4 inch to 1/2 inch
Wire feed speed
5.8 to 12.5 L/min

15. List the basic equipment requirements for the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%
The resistace to electrical current flow increases with it. Causing the electrode to heat

16. What is the purpose of a regulator and what does it indicate on its gauges?
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination

17. What processes are constant current (CC) power sources designed to be used with?
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
Guns
SMAW - GTAW

18. What is the purpose of the shielding gas used in GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone

19. Why must CO2 cylinders be used in the vertical position?
Higher 26 to 35 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

20. How are GMAW guns rated?
85%
Aluminum wire
By there current carrying capacity
Gives arc voltage values to the control system of the feeder

21. What is the key advantage of short circuiting transfer?
20 to 200 times per second
Minimum distortion due to low heat input
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity

22. What controls the wire speed on a voltage sensing wire feeder?
Guns
Wire feed speed
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)

23. What is the required arc voltage used for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
Penetration and burn - off rate of the electrode
Pressure vessels and the piping industry

24. What is an advantage of pulsed arc transfer with GMAW?
National Electrical Manufactures Association
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
3
If you dont know this check your phone

25. What controls amperage when using GMAW?
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer
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

26. What does inductance control?
Reducing the gas source pressure to a constant working pressure
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
Motor driven generators - Transformer rectifiers - and Inverter designs

27. Why is the term GMAW preferred over MIG or MAG?
Spatter problems and poor weld appearance
Wire feed speed
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed

28. Why is a line heater required when using GMAW?
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
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow

29. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input

30. List several industries that would use GMAW
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
Pressure vessels and the piping industry

31. What are the 2 types of wire feeders available?
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feeds smoothly (yet will slip should a problem occur in the gun)

32. What type of power source is used with a constant speed wire feeder?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant voltage (CV)
Welding process that joins metals by heating them with an electric arc
To limit the short circuiting current so that spatter is reduced

33. List 3 wire drive systems and give a short description of each
12 to 22 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
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
If you dont know this check your phone

34. 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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

35. What is the preferred drive roll design for solid 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
5.8 to 12.5 L/min
V groove or U groove
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

36. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Guns
Insufficient current to melt the wire off cleanly

37. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
5.8 to 12.5 L/min
These terms are quite restrictive and often technically incorrect

38. What is the effect of too much slope?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly

39. What does the term GMAW identify?
Gas metal arc welding
Penetration and burn - off rate of the electrode
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

40. In the GMAW process what does voltage control?
The negative side of a welding unit
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity

41. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
If you dont know this check your phone

42. What effect does increasing and decreasing the inductance have on the weld?
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
3
Wire feed speed - Voltage control

43. In the GMAW process what does amperage control?
V groove or U groove
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Penetration and burn - off rate of the electrode

44. What 2 controls are found on a GMAW set- up?
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
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

45. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
When the filler wire is in direct contract with the base metal
...
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
85%

46. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders

47. What is the recommended electrode stick- out for .035 solid wire?
Minimum distortion due to low heat input
1/4 inch to 1/2 inch
Minutes of elapsed time continually run (out of 10 minutes)
Speed of the feed motor and - starting / stopping electrode feed

48. Draw a typical volt amp curve for a machine that is designed for GMAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone
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

49. What is the maximum distance that hard wire can be successfully pushed?
Speed of the feed motor and - starting / stopping electrode feed
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle

50. When is the metal transferred with short circuit transfer?
National Electrical Manufactures Association
3
When the filler wire is in direct contract with the base metal
Dry ice can form within the flow control openings and cause blockage of shielding gas