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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
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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 is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
Minimum distortion due to low heat input
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs

2. When is the metal transferred with short circuit transfer?
AWS and CSA
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal
Wire feed speed

3. What is the purpose of the shielding gas used in GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
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
To limit the short circuiting current so that spatter is reduced

4. List several industries that would use GMAW
Higher 26 to 35 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

5. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding

6. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%

7. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
The Arc voltage
National Electrical Manufactures Association
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity

8. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure

9. What is the preferred drive roll design for solid wires?
1/4 inch to 1/2 inch
If you dont know this check your phone
V groove or U groove
Flux cored wires

10. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Pressure vessels and the piping industry
The negative side of a welding unit
These terms are quite restrictive and often technically incorrect

11. With straight polarity where is 2/3 of the arc energy?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle
The negative side of a welding unit
Cause flaking - which can clog the liner and contact tube

12. What current and polarity is generally used with GMAW?
By there current carrying capacity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity

13. What controls the wire speed on a voltage sensing wire feeder?
20 to 200 times per second
The Arc voltage
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

14. A pull type drive system is usually used on what type of material?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
20 to 200 times per second

15. Why is a fiber washer required and what cylinder gas requires it?
3
SMAW - GTAW
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc

16. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Gas metal arc welding
Spatter problems and poor weld appearance
Minimum distortion due to low heat input

17. What does inductance control?
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure
The time rate of response for the current rise and fall
The negative side of a welding unit

18. List the factors that determine the mode of metal transfer
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant- speed wire feeders and Voltage- sennsing wire feeders

19. Why is a line heater required when using GMAW?
V groove or U groove
Generally not as accurate
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat

20. In the GMAW process what does voltage control?
AWS and CSA
Wire feed speed
These terms are quite restrictive and often technically incorrect
Puddle fluidity

21. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
Constant current (CC)
3

22. List the three methods of metal transfer with GMAW
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle

23. Why must CO2 cylinders be used in the vertical position?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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)
1/4 inch to 1/2 inch

24. What does voltage do in an electrical circuit?
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
Aluminum wire

25. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The resistace to electrical current flow increases with it. Causing the electrode to heat

26. What controls amperage when using GMAW?
5.8 to 12.5 L/min
85%
Wire feed speed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

27. What is an advantage of pulsed arc transfer with GMAW?
V groove or U groove
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

28. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
By there current carrying capacity
3

29. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Gives arc voltage values to the control system of the feeder
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas

30. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect
Constant current (CC)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

31. Give a description of 'pinch effect'
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed

32. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The Arc voltage
Gives arc voltage values to the control system of the feeder
Wire feed speed
Spatter problems and poor weld appearance

33. Regulators control_____________ flowmeters SHOW____________.
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Pressure - The rate of flow of a shielding gas

34. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry

35. List the basic equipment requirements for the GMAW process
3
Cause flaking - which can clog the liner and contact tube
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect

36. What 2 organizations designate specifications for GMAW wires?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
AWS and CSA
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure - The rate of flow of a shielding gas

37. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Guns
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

38. What does the term GMAW identify?
Insufficient current to melt the wire off cleanly
Gas metal arc welding
Puddle fluidity
Shielding the molten weld metal from atmospheric contamination

39. List 3 wire drive systems and give a short description of each
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or 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
National Electrical Manufactures Association

40. Why is globular transfer generally avoided with GMAW?
If you dont know this check your phone
15 feet (4.5 meters)
Spatter problems and poor weld appearance
By there current carrying capacity

41. List 3 forms compressed gases may be supplied for welding
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
12 to 22 arc volts
Constant voltage (CV)

42. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Wire feed speed - Voltage control
If you dont know this check your phone
Generally not as accurate
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

43. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Voltage is the force that overcomes resistance to allow amperage flow
The time rate of response for the current rise and fall
...
Constant voltage (CV)

44. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Pressure vessels and the piping industry
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube

45. How many times per second does short circuiting take place?
Shielding the molten weld metal from atmospheric contamination
...
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

46. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
Wire feed speed - Voltage control

47. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
...

48. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
3
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed

49. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly

50. What is the recommended electrode stick- out for .035 solid wire?
The negative side of a welding unit
1/4 inch to 1/2 inch
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
Voltage is the force that overcomes resistance to allow amperage flow