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. A pull type drive system is usually used on what type of material?
Gas metal arc welding
If you dont know this check your phone
3
Aluminum wire

2. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity

3. What controls amperage when using 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
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
Wire feed speed

4. Give a brief description of the GMAW process
12 to 22 arc volts
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control

5. List the three methods of metal transfer with GMAW
Speed of the feed motor and - starting / stopping electrode feed
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Short- circuiting transfer - Globular transfer - Spray transfer

6. When is the metal transferred with short circuit transfer?
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
When the filler wire is in direct contract with the base metal
Motor driven generators - Transformer rectifiers - and Inverter designs

7. What controls the wire speed on a voltage sensing wire feeder?
By there current carrying capacity
Guns
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage

8. What is the maximum distance that hard wire can be successfully pushed?
By there current carrying capacity
Flux cored wires
15 feet (4.5 meters)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

9. List several industries that would use GMAW
Pressure vessels and the piping industry
Motor driven generators - Transformer rectifiers - and Inverter designs
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc

10. What does the abbreviation NEMA stand for?
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
To prevent leakage - Carbon Dioxide (CO2)
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal

11. What processes are constant current (CC) power sources designed to be used with?
The Arc voltage
Voltage is the force that overcomes resistance to allow amperage flow
SMAW - GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders

12. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Flux cored wires

13. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
The negative side of a welding unit
1/4 inch to 1/2 inch

14. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Aluminum wire
When the filler wire is in direct contract with the base metal
AWS and CSA
...

15. Why is a line heater required when using GMAW?
1/4 inch to 1/2 inch
Reducing the gas source pressure to a constant working pressure
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas

16. What is the purpose of the shielding gas used in GMAW?
5.8 to 12.5 L/min
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
To prevent leakage - Carbon Dioxide (CO2)

17. What is a typical flow rate of CO2 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
Minutes of elapsed time continually run (out of 10 minutes)
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

18. 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
If you dont know this check your phone
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
If you dont know this check your phone
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
Higher 26 to 35 arc volts

20. What output on the welding machine is used to rate the duty cycle?
The Arc voltage
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min
Minutes of elapsed time continually run (out of 10 minutes)

21. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
SMAW - GTAW
3
85%
Penetration and burn - off rate of the electrode

22. What is another term for electrode holders for GMAW?
Guns
National Electrical Manufactures Association
To prevent drawing of liquid CO2 (Carbon Dioxide)
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

23. What 2 organizations designate specifications for GMAW wires?
Flux cored wires
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity
85%

24. Give a description of 'pinch effect'
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage

25. Regulators control_____________ flowmeters SHOW____________.
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas
The negative side of a welding unit
3

26. Why must CO2 cylinders be used in the vertical position?
Voltage is the force that overcomes resistance to allow amperage flow
Shielding the molten weld metal from atmospheric contamination
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent drawing of liquid CO2 (Carbon Dioxide)

27. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
(DCEP) Direct Current Electrode Positive or Reverse polarity
The negative side of a welding unit
Insufficient current to melt the wire off cleanly
3

28. List the factors that determine the mode of metal transfer
The Arc voltage
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
DCEP (Direct Current Electrode Positive) Reverse Polarity

29. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry

30. How many times per second does short circuiting take place?
The Arc voltage
5.8 to 12.5 L/min
20 to 200 times per second
85%

31. What is the key advantage of short circuiting transfer?
Guns
Minimum distortion due to low heat input
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

32. What is a solenoid valve and what actuates it?
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant current (CC)
Constant voltage (CV)

33. What is the preferred drive roll design for solid wires?
Higher 26 to 35 arc volts
V groove or U groove
Guns
When the filler wire is in direct contract with the base metal

34. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle

35. What is an advantage of pulsed arc transfer with GMAW?
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed

36. Why is a fiber washer required and what cylinder gas requires it?
Penetration and burn - off rate of the electrode
AWS and CSA
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)

37. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
3
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
20 to 200 times per second

38. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association

39. What does the term GMAW identify?
National Electrical Manufactures Association
Gas metal arc welding
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect

40. List the basic equipment requirements for the GMAW process
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

41. What is the purpose of a regulator and what does it indicate on its gauges?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Generally not as accurate
Duty cycle
Reducing the gas source pressure to a constant working pressure

42. Draw a typical volt amp curve for a machine that is designed for GMAW
Insufficient current to melt the wire off cleanly
Aluminum wire
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

43. In the GMAW process what does amperage control?
Puddle fluidity
Penetration and burn - off rate of the electrode
3
Guns

44. What type of power source is commonly used with a voltage sensing wire feeder?
National Electrical Manufactures Association
The time rate of response for the current rise and fall
1/4 inch to 1/2 inch
Constant current (CC)

45. What are the 2 types of wire feeders available?
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders
...
Dry ice can form within the flow control openings and cause blockage of shielding gas

46. Why is globular transfer generally avoided with GMAW?
By there current carrying capacity
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
3

47. What is the recommended electrode stick- out for .035 solid wire?
The time rate of response for the current rise and fall
Pressure vessels and the piping industry
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode

48. What does a flowmeter do and what does it measure?
Puddle fluidity
20 to 200 times per second
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone

49. List 3 forms compressed gases may be supplied for welding
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

50. 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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control