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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. Why is a fiber washer required and what cylinder gas requires it?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode

2. What current and polarity is generally used with GMAW?
Spatter problems and poor weld appearance
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)

3. What is a solenoid valve and what actuates it?
Short- circuiting transfer - Globular transfer - Spray transfer
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Reducing the gas source pressure to a constant working pressure
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

4. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Duty cycle
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced

5. What is the recommended electrode stick- out for .035 solid wire?
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer
1/4 inch to 1/2 inch

6. What would be an indication that the drive roll pressure is adjusted correctly?
The negative side of a welding unit
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
Gives arc voltage values to the control system of the feeder

7. 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)
National Electrical Manufactures Association
The negative side of a welding unit
Minutes of elapsed time continually run (out of 10 minutes)

8. In the GMAW process what does amperage control?
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)
Generally not as accurate
Penetration and burn - off rate of the electrode

9. What 2 organizations designate specifications for GMAW wires?
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc
AWS and CSA
Puddle fluidity

10. List 3 forms compressed gases may be supplied for welding
The Arc voltage
Puddle fluidity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)

11. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed

12. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Shielding the molten weld metal from atmospheric contamination
Cause flaking - which can clog the liner and contact tube
Guns
Speed of the feed motor and - starting / stopping electrode feed

13. Give a brief description of the GMAW process
Short- circuiting transfer - Globular transfer - Spray transfer
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

14. Give a description of 'pinch effect'
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Shielding the molten weld metal from atmospheric contamination

15. A pull type drive system is usually used on what type of material?
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Aluminum wire

16. What is another term for electrode holders for GMAW?
1/4 inch to 1/2 inch
National Electrical Manufactures Association
Guns
Gas metal arc welding

17. When is the metal transferred with short circuit transfer?
Wire feed speed - Voltage control
Wire feed speed
Generally not as accurate
When the filler wire is in direct contract with the base metal

18. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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

19. Draw a typical volt amp curve for a machine that is designed for GMAW
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit
If you dont know this check your phone

20. How many times per second does short circuiting take place?
Flux cored wires
3
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
20 to 200 times per second

21. What is a typical flow rate of CO2 for short circuit transfer?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Wire feed speed

22. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Guns
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control

23. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Generally not as accurate

24. List 3 wire drive systems and give a short description of each
If you dont know this check your phone
To prevent leakage - Carbon Dioxide (CO2)
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
Controls the rate of flow of a shielding gas to the gun nozzle

25. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
12 to 22 arc volts
When the filler wire is in direct contract with the base metal

26. List the factors that determine the mode of metal transfer
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Guns
The Arc voltage

27. What type of power source is commonly used with a voltage sensing wire feeder?
Speed of the feed motor and - starting / stopping electrode feed
Constant current (CC)
Generally not as accurate
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

28. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Duty cycle
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gives arc voltage values to the control system of the feeder

29. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas
85%
Penetration and burn - off rate of the electrode

30. What controls amperage when using GMAW?
Wire feed speed
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure - The rate of flow of a shielding gas

31. What 2 controls are found on a GMAW set- up?
Duty cycle
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
If you dont know this check your phone

32. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
National Electrical Manufactures Association
By there current carrying capacity

33. With straight polarity where is 2/3 of the arc energy?
These terms are quite restrictive and often technically incorrect
The negative side of a welding unit
Constant voltage (CV)
1/4 inch to 1/2 inch

34. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts
Gas metal arc welding
The resistace to electrical current flow increases with it. Causing the electrode to heat

35. What does inductance control?
To limit the short circuiting current so that spatter is reduced
The time rate of response for the current rise and fall
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent leakage - Carbon Dioxide (CO2)

36. What type of power source is used with a constant speed wire feeder?
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)
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

37. How are GMAW guns rated?
...
By there current carrying capacity
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)

38. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)
Flux cored wires
85%

39. What effect does increasing and decreasing the inductance have on the weld?
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Flux cored wires

40. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The negative side of a welding unit
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect

41. What wire are knurled drive rolls most commonly used on?
Gives arc voltage values to the control system of the feeder
Flux cored wires
Pressure vessels and the piping industry
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

42. What processes are constant current (CC) power sources designed to be used with?
Welding process that joins metals by heating them with an electric arc
SMAW - GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Shielding the molten weld metal from atmospheric contamination

43. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
These terms are quite restrictive and often technically incorrect
Minutes of elapsed time continually run (out of 10 minutes)
The Arc voltage
If you dont know this check your phone

44. What is the key advantage of short circuiting transfer?
The Arc voltage
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input

45. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

46. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly

47. What is the preferred drive roll design for solid 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
V groove or U groove
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

48. Why is the term GMAW preferred over MIG or MAG?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced

49. What power sources are used with the GMAW Process?
1/4 inch to 1/2 inch
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone

50. What is the purpose of the shielding gas used in GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed