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 machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
V groove or U groove
Duty cycle
Generally not as accurate

2. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly
V groove or U groove
Motor driven generators - Transformer rectifiers - and Inverter designs

3. What is a solenoid valve and what actuates it?
Generally not as accurate
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
Minutes of elapsed time continually run (out of 10 minutes)

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder
To prevent drawing of liquid CO2 (Carbon Dioxide)
Flux cored wires

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
85%
Aluminum wire
If you dont know this check your phone
Generally not as accurate

6. List 3 forms compressed gases may be supplied for welding
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
By there current carrying capacity
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

7. Give a brief description of the GMAW process
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder

8. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Guns
Wire feed speed - Voltage control

9. What effect does increasing and decreasing the inductance have on the weld?
Gas metal arc welding
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Dry ice can form within the flow control openings and cause blockage of shielding gas

10. What is an advantage of pulsed arc transfer with GMAW?
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The negative side of a welding unit

11. List 3 wire drive systems and give a short description of each
If you dont know this check your phone
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
12 to 22 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

12. How are GMAW guns rated?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc

13. What does a flowmeter do and what does it measure?
...
Voltage is the force that overcomes resistance to allow amperage flow
Controls the rate of flow of a shielding gas to the gun nozzle
The time rate of response for the current rise and fall

14. 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
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)
To prevent leakage - Carbon Dioxide (CO2)

15. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Pressure vessels and the piping industry
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity

16. What is another term for electrode holders for GMAW?
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
20 to 200 times per second

17. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW
When the filler wire is in direct contract with the base metal

18. How many times per second does short circuiting take place?
(DCEP) Direct Current Electrode Positive or Reverse polarity
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed - Voltage control

19. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
SMAW - GTAW
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

20. In the GMAW process what does amperage control?
Constant current (CC)
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

21. What type of power source is commonly used with a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)

22. What current and polarity is generally used with GMAW?
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity
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 are the 2 types of wire feeders available?
The time rate of response for the current rise and fall
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal

24. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

25. List the factors that determine the mode of metal transfer
To limit the short circuiting current so that spatter is reduced
...
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%

26. List the three methods of metal transfer with GMAW
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer
3
Constant current (CC)

27. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
By there current carrying capacity
Duty cycle
Pressure vessels and the piping industry

28. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
Higher 26 to 35 arc volts
15 feet (4.5 meters)

29. What does the wire feeder control?
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
Speed of the feed motor and - starting / stopping electrode feed

30. What type of power source is used with a constant speed wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Cause flaking - which can clog the liner and contact tube
Constant voltage (CV)
Wire feeds smoothly (yet will slip should a problem occur in the gun)

31. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
The time rate of response for the current rise and fall
Minutes of elapsed time continually run (out of 10 minutes)
Duty cycle

32. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
Pressure vessels and the piping industry

33. List the basic equipment requirements for the GMAW process
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
Gives arc voltage values to the control system of the feeder
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA

34. List several industries that would use GMAW
The time rate of response for the current rise and fall
3
Pressure vessels and the piping industry
To prevent drawing of liquid CO2 (Carbon Dioxide)

35. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed

36. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire
Short- circuiting transfer - Globular transfer - Spray transfer
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

37. Why is the term GMAW preferred over MIG or MAG?
20 to 200 times per second
Generally not as accurate
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc

38. What is the required arc voltage used for short circuit transfer?
1/4 inch to 1/2 inch
Guns
12 to 22 arc volts
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

39. What would be an indication that the drive roll pressure is adjusted correctly?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly
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

40. What is the effect of too much slope?
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
Constant voltage (CV)
Gas metal arc welding

41. Regulators control_____________ flowmeters SHOW____________.
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
Pressure - The rate of flow of a shielding gas
Constant voltage (CV)

42. What processes are constant current (CC) power sources designed to be used with?
Shielding the molten weld metal from atmospheric contamination
The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW
Wire feed speed - Voltage control

43. What 2 organizations designate specifications for GMAW wires?
Wire feed speed
Pressure - The rate of flow of a shielding gas
AWS and CSA
Dry ice can form within the flow control openings and cause blockage of shielding gas

44. What is the key advantage of short circuiting transfer?
Puddle fluidity
Constant current (CC)
Minimum distortion due to low heat input
1/4 inch to 1/2 inch

45. What is the purpose of the shielding gas used in GMAW?
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry

46. What output on the welding machine is used to rate the duty cycle?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding process that joins metals by heating them with an electric arc
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)

47. What controls amperage when using GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
These terms are quite restrictive and often technically incorrect
Wire feed speed
Wire feed speed - Voltage control

48. Give a description of 'pinch effect'
Minimum distortion due to low heat input
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
20 to 200 times per second
By there current carrying capacity

49. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Gas metal arc welding
...
Short- circuiting transfer - Globular transfer - Spray transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas

50. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second
12 to 22 arc volts