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 wire are knurled drive rolls most commonly used on?
Flux cored wires
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs

2. What does the term GMAW identify?
Gas metal arc welding
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feed speed - Voltage control
Minimum distortion due to low heat input

3. What current and polarity is generally used with GMAW?
When the filler wire is in direct contract with the base metal
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Puddle fluidity
DCEP (Direct Current Electrode Positive) Reverse Polarity

4. What type of power source is used with a constant speed wire feeder?
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
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone

5. Draw a typical volt amp curve for a machine that is designed for GMAW
AWS and CSA
12 to 22 arc volts
If you dont know this check your phone
Generally not as accurate

6. What is an advantage of pulsed arc transfer with GMAW?
Gives arc voltage values to the control system of the feeder
Insufficient current to melt the wire off cleanly
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Puddle fluidity

7. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
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
5.8 to 12.5 L/min

8. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Reducing the gas source pressure to a constant working pressure
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant current (CC)

9. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The negative side of a welding unit
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate

10. What is the disadvantage of the gauge preset type of regulator/flowmeter?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant current (CC)
Generally not as accurate
20 to 200 times per second

11. What effect does increasing and decreasing the inductance have on the weld?
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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

12. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure vessels and the piping industry
Gives arc voltage values to the control system of the feeder
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

13. What is a solenoid valve and what actuates it?
Flux cored wires
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
SMAW - GTAW

14. What output on the welding machine is used to rate the duty cycle?
Aluminum wire
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts
Minutes of elapsed time continually run (out of 10 minutes)

15. What is the required arc voltage used for short circuit transfer?
Wire feed speed - Voltage control
Short- circuiting transfer - Globular transfer - Spray transfer
12 to 22 arc volts
National Electrical Manufactures Association

16. What would be an indication that the drive roll pressure is adjusted correctly?
85%
Minutes of elapsed time continually run (out of 10 minutes)
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)

17. What is the main purpose of 'slope'?
5.8 to 12.5 L/min
3
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced

18. What is another term for electrode holders for GMAW?
Guns
Higher 26 to 35 arc volts
Spatter problems and poor weld appearance
When the filler wire is in direct contract with the base metal

19. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
V groove or U groove
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

20. What is the key advantage of short circuiting transfer?
The Arc voltage
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity

21. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs
Cause flaking - which can clog the liner and contact tube

22. What is the maximum distance that hard wire can be successfully pushed?
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)
Gas metal arc welding
12 to 22 arc volts

23. How many times per second does short circuiting take place?
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube
The time rate of response for the current rise and fall

24. Why is globular transfer generally avoided with GMAW?
Pressure - The rate of flow of a shielding gas
Wire feed speed - Voltage control
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

25. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Constant current (CC)
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
Cause flaking - which can clog the liner and contact tube

26. What controls amperage when using GMAW?
85%
Duty cycle
Wire feed speed
Flux cored wires

27. In the GMAW process what does amperage control?
Gives arc voltage values to the control system of the feeder
Generally not as accurate
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Penetration and burn - off rate of the electrode

28. What is the recommended electrode stick- out for .035 solid wire?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
1/4 inch to 1/2 inch

29. What power sources are used with the GMAW Process?
Generally not as accurate
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
Motor driven generators - Transformer rectifiers - and Inverter designs

30. A 10 minute cycle of welding time vs cooling time a given machine can handle.
...
Duty cycle
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove

31. What does a flowmeter do and what does it measure?
1/4 inch to 1/2 inch
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed - Voltage control
Controls the rate of flow of a shielding gas to the gun nozzle

32. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
If you dont know this check your phone
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

33. What 2 organizations designate specifications for GMAW wires?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
AWS and CSA

34. How are GMAW guns rated?
By there current carrying capacity
Constant voltage (CV)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed

35. 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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Generally not as accurate
5.8 to 12.5 L/min

36. Why is the term GMAW preferred over MIG or MAG?
Minimum distortion due to low heat input
These terms are quite restrictive and often technically incorrect
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode

37. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
These terms are quite restrictive and often technically incorrect

38. List the factors that determine the mode of metal transfer
Reducing the gas source pressure to a constant working pressure
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
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

39. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
12 to 22 arc volts
National Electrical Manufactures Association
Reducing the gas source pressure to a constant working pressure
...

40. What controls the wire speed on a voltage sensing wire feeder?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)

41. List 3 wire drive systems and give a short description of each
DCEP (Direct Current Electrode Positive) Reverse Polarity
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
Short- circuiting transfer - Globular transfer - Spray transfer

42. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Reducing the gas source pressure to a constant working pressure
Generally not as accurate
Higher 26 to 35 arc volts
Insufficient current to melt the wire off cleanly

43. What is the preferred drive roll design for solid wires?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Aluminum wire
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow

44. In the GMAW process what does voltage control?
15 feet (4.5 meters)
Aluminum wire
Puddle fluidity
3

45. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Constant voltage (CV)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced

46. What processes are constant current (CC) power sources designed to be used with?
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure

47. What does the abbreviation NEMA stand for?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

48. List the basic equipment requirements for the GMAW process
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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association

49. What does inductance control?
...
The time rate of response for the current rise and fall
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Flux cored wires

50. 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
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Voltage is the force that overcomes resistance to allow amperage flow