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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 are the 2 types of wire feeders available?
Duty cycle
...
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders

2. What wire are knurled drive rolls most commonly used on?
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity

3. How are GMAW guns rated?
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed
3
By there current carrying capacity

4. In the GMAW process what does voltage control?
Gas metal arc welding
Flux cored wires
Shielding the molten weld metal from atmospheric contamination
Puddle fluidity

5. What is the recommended electrode stick- out for .035 solid wire?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder
Minutes of elapsed time continually run (out of 10 minutes)

6. 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
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect

7. What would be an indication that the drive roll pressure is adjusted correctly?
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)

8. A pull type drive system is usually used on what type of material?
Spatter problems and poor weld appearance
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
Aluminum wire

9. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Minimum distortion due to low heat input
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
Aluminum wire

10. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min

11. List several industries that would use GMAW
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
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

12. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
SMAW - GTAW
...
Minimum distortion due to low heat input

13. 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
Shielding the molten weld metal from atmospheric contamination
1/4 inch to 1/2 inch

14. Why is the term GMAW preferred over MIG or MAG?
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Insufficient current to melt the wire off cleanly
These terms are quite restrictive and often technically incorrect

15. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle

16. What does voltage do in an electrical circuit?
15 feet (4.5 meters)
AWS and CSA
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Voltage is the force that overcomes resistance to allow amperage flow

17. Why is a line heater required when using GMAW?
Constant voltage (CV)
12 to 22 arc volts
Wire feed speed - Voltage control
Dry ice can form within the flow control openings and cause blockage of shielding gas

18. What is the preferred drive roll design for solid wires?
V groove or U groove
Speed of the feed motor and - starting / stopping electrode feed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Generally not as accurate
20 to 200 times per second
Constant voltage (CV)
85%

20. Regulators control_____________ flowmeters SHOW____________.
85%
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

21. What does a flowmeter do and what does it measure?
Gas metal arc welding
Constant voltage (CV)
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)

22. What controls the wire speed on a voltage sensing wire feeder?
Welding process that joins metals by heating them with an electric arc
The Arc voltage
20 to 200 times per second
1/4 inch to 1/2 inch

23. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Constant voltage (CV)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs

24. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
12 to 22 arc volts

25. How many times per second does short circuiting take place?
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gives arc voltage values to the control system of the feeder
Aluminum wire

26. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gives arc voltage values to the control system of the feeder
...
V groove or U groove

27. Give a description of 'pinch effect'
Aluminum wire
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

28. What is an advantage of pulsed arc transfer with GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube
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

29. What happens when the electrode extension is increased?
Guns
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed

30. List 3 wire drive systems and give a short description of each
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)

31. What power sources are used with the GMAW Process?
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs

32. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity

34. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit

35. What is the key advantage of short circuiting transfer?
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input
Generally not as accurate
The time rate of response for the current rise and fall

36. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Guns
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)

37. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)

38. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
5.8 to 12.5 L/min
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity

39. What type of power source is used with a constant speed wire feeder?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant voltage (CV)
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

40. What controls amperage when using GMAW?
5.8 to 12.5 L/min
20 to 200 times per second
Wire feed speed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

41. What is the main purpose of 'slope'?
Guns
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

42. When is the metal transferred with short circuit transfer?
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
Reducing the gas source pressure to a constant working pressure
When the filler wire is in direct contract with the base metal

43. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant current (CC)

44. Why is globular transfer generally avoided with GMAW?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Spatter problems and poor weld appearance
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder

45. What does inductance control?
The time rate of response for the current rise and fall
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
Pressure vessels and the piping industry

46. What does the term GMAW identify?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced
Wire feed speed

47. List the basic equipment requirements for the GMAW process
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Motor driven generators - Transformer rectifiers - and Inverter designs

48. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination

49. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Controls the rate of flow of a shielding gas to the gun nozzle
Guns
Wire feeds smoothly (yet will slip should a problem occur in the gun)

50. What is a solenoid valve and what actuates it?
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts
Penetration and burn - off rate of the electrode