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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 30 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. In the GMAW process what does voltage control?
When the filler wire is in direct contract with the base metal
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)

2. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
The negative side of a welding unit
12 to 22 arc volts
Pressure vessels and the piping industry

3. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Wire feed speed - Voltage control
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)

4. What output on the welding machine is used to rate the duty cycle?
Gives arc voltage values to the control system of the feeder
Minutes of elapsed time continually run (out of 10 minutes)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

5. Regulators control_____________ flowmeters SHOW____________.
5.8 to 12.5 L/min
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas

6. What processes are constant current (CC) power sources designed to be used with?
Minimum distortion due to low heat input
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
If you dont know this check your phone

7. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Generally not as accurate

8. What controls the wire speed on a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage
1/4 inch to 1/2 inch

9. Draw a typical volt amp curve for a machine that is designed for GMAW
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
Generally not as accurate
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

10. What is the required arc voltage used for short circuit transfer?
Gives arc voltage values to the control system of the feeder
12 to 22 arc volts
Wire feed speed
Pressure vessels and the piping industry

11. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Cause flaking - which can clog the liner and contact tube
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
85%

12. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry

13. 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)
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
Minutes of elapsed time continually run (out of 10 minutes)

14. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Minimum distortion due to low heat input
If you dont know this check your phone
Spatter problems and poor weld appearance
Pressure - The rate of flow of a shielding gas

15. Why must CO2 cylinders be used in the vertical position?
Penetration and burn - off rate of the electrode
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
To prevent drawing of liquid CO2 (Carbon Dioxide)

16. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
To limit the short circuiting current so that spatter is reduced
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
V groove or U groove

17. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gives arc voltage values to the control system of the feeder

18. What does the term GMAW identify?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)

19. Give a brief description of the GMAW process
Pressure - The rate of flow of a shielding gas
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc
Higher 26 to 35 arc volts

20. 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
V groove or U groove
DCEP (Direct Current Electrode Positive) Reverse Polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

21. How many times per second does short circuiting take place?
The time rate of response for the current rise and fall
20 to 200 times per second
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder

22. What controls amperage when using GMAW?
Wire feed speed
Constant current (CC)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed - Voltage control

23. When is the metal transferred with short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal

24. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts
Generally not as accurate

25. What is a solenoid valve and what actuates it?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association
5.8 to 12.5 L/min

26. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
15 feet (4.5 meters)
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed

27. What type of power source is commonly used with a voltage sensing wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

28. What is the effect of too much slope?
Welding process that joins metals by heating them with an electric arc
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall

29. How are GMAW guns rated?
Higher 26 to 35 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
By there current carrying capacity
Aluminum wire

30. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Shielding the molten weld metal from atmospheric contamination
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders

31. With straight polarity where is 2/3 of the arc energy?
15 feet (4.5 meters)
Puddle fluidity
The negative side of a welding unit
The resistace to electrical current flow increases with it. Causing the electrode to heat

32. What is another term for electrode holders for GMAW?
Guns
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)

33. List 3 wire drive systems and give a short description of each
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
Gas metal arc welding
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube

34. List the three methods of metal transfer with GMAW
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gives arc voltage values to the control system of the feeder

35. 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
The time rate of response for the current rise and fall
12 to 22 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Voltage is the force that overcomes resistance to allow amperage flow
To limit the short circuiting current so that spatter is reduced
Penetration and burn - off rate of the electrode

37. What is the recommended electrode stick- out for .035 solid wire?
Wire feed speed
1/4 inch to 1/2 inch
V groove or U groove
When the filler wire is in direct contract with the base metal

38. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
National Electrical Manufactures Association
20 to 200 times per second
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder

39. List several industries that would use GMAW
Pressure vessels and the piping industry
The time rate of response for the current rise and fall
By there current carrying capacity
When the filler wire is in direct contract with the base metal

40. Why is a fiber washer required and what cylinder gas requires it?
...
Shielding the molten weld metal from atmospheric contamination
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW

41. What current and polarity is generally used with GMAW?
85%
SMAW - GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

42. What type of power source is used with a constant speed wire feeder?
5.8 to 12.5 L/min
Constant voltage (CV)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
When the filler wire is in direct contract with the base metal

43. What is the key advantage of short circuiting transfer?
20 to 200 times per second
Minimum distortion due to low heat input
The time rate of response for the current rise and fall
12 to 22 arc volts

44. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Pressure - The rate of flow of a shielding gas
...
If you dont know this check your phone
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

45. What does inductance control?
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
The time rate of response for the current rise and fall

46. What is the preferred drive roll design for solid wires?
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)
12 to 22 arc volts
V groove or U groove

47. A pull type drive system is usually used on what type of material?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Aluminum wire
20 to 200 times per second
3

48. What power sources are used with the GMAW Process?
Duty cycle
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)

49. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
3

50. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3
By there current carrying capacity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground