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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 does inductance control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)

2. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
By there current carrying capacity
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit

3. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Higher 26 to 35 arc volts
Flux cored wires
Cause flaking - which can clog the liner and contact tube

4. What is a solenoid valve and what actuates it?
Duty cycle
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

5. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
85%
...
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)

6. List the basic equipment requirements for the GMAW process
AWS and CSA
By there current carrying capacity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

7. Why is a line heater required when using GMAW?
Cause flaking - which can clog the liner and contact tube
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...

8. What 2 organizations designate specifications for GMAW wires?
Guns
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
AWS and CSA

9. In the GMAW process what does voltage control?
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
Puddle fluidity

10. 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
Reducing the gas source pressure to a constant working pressure
Wire feed speed - Voltage control

11. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Generally not as accurate
The Arc voltage
V groove or U groove

12. What controls amperage when using GMAW?
Pressure vessels and the piping industry
3
Wire feed speed
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

13. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...
These terms are quite restrictive and often technically incorrect

14. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode
...

15. A pull type drive system is usually used on what type of material?
Aluminum wire
Constant voltage (CV)
1/4 inch to 1/2 inch
V groove or U groove

16. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
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
SMAW - GTAW
Gas metal arc welding

17. What is the purpose of the shielding gas used in GMAW?
Constant voltage (CV)
Wire feed speed - Voltage control
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

18. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
The Arc voltage
12 to 22 arc volts
3

19. 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
These terms are quite restrictive and often technically incorrect
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
(DCEP) Direct Current Electrode Positive or Reverse polarity

20. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)
Motor driven generators - Transformer rectifiers - and Inverter designs

21. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Flux cored wires
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

22. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
3

23. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
If you dont know this check your phone
The Arc voltage
National Electrical Manufactures Association

24. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Wire feed speed - Voltage control
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

25. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
The Arc voltage
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association

26. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Spatter problems and poor weld appearance
Flux cored wires
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

27. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Aluminum wire

28. What is a typical flow rate of CO2 for short circuit transfer?
Guns
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc
5.8 to 12.5 L/min

29. How are GMAW guns rated?
SMAW - GTAW
The negative side of a welding unit
Constant current (CC)
By there current carrying capacity

30. List 3 forms compressed gases may be supplied for welding
Reducing the gas source pressure to a constant working pressure
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

31. What output on the welding machine is used to rate the duty cycle?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding process that joins metals by heating them with an electric arc

32. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second
...

33. List 3 wire drive systems and give a short description of each
20 to 200 times per second
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed
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

34. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
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
To prevent leakage - Carbon Dioxide (CO2)
85%

35. What effect does increasing and decreasing the inductance have on the weld?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

36. What does the term GMAW identify?
Reducing the gas source pressure to a constant working pressure
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity

37. What is the key advantage of short circuiting transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minimum distortion due to low heat input
SMAW - GTAW

38. What type of power source is commonly used with a voltage sensing wire feeder?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant voltage (CV)
Constant current (CC)
These terms are quite restrictive and often technically incorrect

39. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
5.8 to 12.5 L/min
Wire feed speed - Voltage control
DCEP (Direct Current Electrode Positive) Reverse Polarity

40. What is the effect of too much slope?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
Insufficient current to melt the wire off cleanly

41. List several industries that would use GMAW
Gas metal arc welding
Gives arc voltage values to the control system of the feeder
Pressure vessels and the piping industry
The resistace to electrical current flow increases with it. Causing the electrode to heat

42. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
The negative side of a welding unit
Wire feed speed
Controls the rate of flow of a shielding gas to the gun nozzle

43. What does a flowmeter do and what does it measure?
Constant voltage (CV)
Controls the rate of flow of a shielding gas to the gun nozzle
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced

44. What are the 2 types of wire feeders available?
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns

45. In the GMAW process what does amperage control?
The time rate of response for the current rise and fall
AWS and CSA
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity

46. What happens when the electrode extension is increased?
...
These terms are quite restrictive and often technically incorrect
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat

47. How many times per second does short circuiting take place?
Guns
15 feet (4.5 meters)
20 to 200 times per second
Constant current (CC)

48. What is another term for electrode holders for GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
85%
Guns

49. What does the wire feeder control?
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
...

50. What does voltage do in an electrical circuit?
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
The resistace to electrical current flow increases with it. Causing the electrode to heat
Voltage is the force that overcomes resistance to allow amperage flow