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 is the purpose of the shielding gas used in GMAW?
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination

2. Why must CO2 cylinders be used in the vertical position?
The negative side of a welding unit
3
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)

3. What effect does increasing and decreasing the inductance have on the weld?
Pressure vessels and the piping industry
Gives arc voltage values to the control system of the feeder
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

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Shielding the molten weld metal from atmospheric contamination
12 to 22 arc volts
Gives arc voltage values to the control system of the feeder

5. What controls the wire speed on a voltage sensing wire feeder?
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Cause flaking - which can clog the liner and contact tube
The Arc voltage

6. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association
Constant current (CC)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

7. What wire are knurled drive rolls most commonly used on?
Duty cycle
Gas metal arc welding
20 to 200 times per second
Flux cored wires

8. In the GMAW process what does amperage control?
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Penetration and burn - off rate of the electrode
Wire feed speed

9. What does the wire feeder control?
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

10. What 2 controls are found on a GMAW set- up?
Shielding the molten weld metal from atmospheric contamination
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

11. What controls amperage when using GMAW?
Wire feed speed
Puddle fluidity
National Electrical Manufactures Association
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

12. What 2 organizations designate specifications for GMAW wires?
Higher 26 to 35 arc volts
Aluminum wire
Constant- speed wire feeders and Voltage- sennsing wire feeders
AWS and CSA

13. A pull type drive system is usually used on what type of material?
Aluminum wire
20 to 200 times per second
To prevent drawing of liquid CO2 (Carbon Dioxide)
(DCEP) Direct Current Electrode Positive or Reverse polarity

14. What type of power source is commonly used with a voltage sensing wire feeder?
Gas metal arc welding
Constant current (CC)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Pressure - The rate of flow of a shielding gas

15. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)
Minimum distortion due to low heat input
Puddle fluidity

16. List several industries that would use GMAW
The Arc voltage
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
Spatter problems and poor weld appearance

17. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Motor driven generators - Transformer rectifiers - and Inverter designs
When the filler wire is in direct contract with the base metal
1/4 inch to 1/2 inch

18. What does the term GMAW identify?
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min
If you dont know this check your phone
Gas metal arc welding

19. What type of power source is used with a constant speed wire feeder?
Flux cored wires
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas

20. What is the recommended electrode stick- out for .035 solid wire?
Wire feed speed - Voltage control
If you dont know this check your phone
1/4 inch to 1/2 inch
The time rate of response for the current rise and fall

21. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Spatter problems and poor weld appearance

22. Why is a line heater required when using GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate
Higher 26 to 35 arc volts

23. List the basic equipment requirements for the GMAW process
National Electrical Manufactures Association
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

24. What is another term for electrode holders for GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
20 to 200 times per second
Guns
These terms are quite restrictive and often technically incorrect

25. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Higher 26 to 35 arc volts

26. List 3 wire drive systems and give a short description of each
These terms are quite restrictive and often technically incorrect
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
15 feet (4.5 meters)
Minimum distortion due to low heat input

27. What does inductance control?
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube
The time rate of response for the current rise and fall
Pressure vessels and the piping industry

28. What are the 2 types of wire feeders available?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer
Controls the rate of flow of a shielding gas to the gun nozzle

29. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
85%
Aluminum wire
...
To prevent drawing of liquid CO2 (Carbon Dioxide)

30. What is the maximum distance that hard wire can be successfully pushed?
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association
Wire feed speed
15 feet (4.5 meters)

31. What is the main purpose of 'slope'?
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
SMAW - GTAW

32. List the factors that determine the mode of metal transfer
Shielding the molten weld metal from atmospheric contamination
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
(DCEP) Direct Current Electrode Positive or Reverse polarity

33. How are GMAW guns rated?
12 to 22 arc volts
...
Flux cored wires
By there current carrying capacity

34. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Gas metal arc welding
V groove or U groove
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity

35. When is the metal transferred with short circuit transfer?
1/4 inch to 1/2 inch
When the filler wire is in direct contract with the base metal
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Puddle fluidity

36. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
Generally not as accurate

37. What processes are constant current (CC) power sources designed to be used with?
Penetration and burn - off rate of the electrode
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW
Short- circuiting transfer - Globular transfer - Spray transfer

38. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
Aluminum wire

39. What happens when the electrode extension is increased?
Duty cycle
15 feet (4.5 meters)
DCEP (Direct Current Electrode Positive) Reverse Polarity
The resistace to electrical current flow increases with it. Causing the electrode to heat

40. Give a brief description of the GMAW process
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect

41. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Duty cycle
15 feet (4.5 meters)
When the filler wire is in direct contract with the base metal

42. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
5.8 to 12.5 L/min
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
1/4 inch to 1/2 inch

43. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Insufficient current to melt the wire off cleanly
85%
The Arc voltage
To prevent drawing of liquid CO2 (Carbon Dioxide)

44. What is the preferred drive roll design for solid wires?
3
Pressure vessels and the piping industry
V groove or U groove
SMAW - GTAW

45. Why is the term GMAW preferred over MIG or MAG?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
These terms are quite restrictive and often technically incorrect

46. What does a flowmeter do and what does it measure?
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
Controls the rate of flow of a shielding gas to the gun nozzle

47. Regulators control_____________ flowmeters SHOW____________.
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
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas

48. Why is a fiber washer required and what cylinder gas requires it?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Flux cored wires
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced

49. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Generally not as accurate
Puddle fluidity

50. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
The Arc voltage
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