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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 must CO2 cylinders be used in the vertical position?
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min

2. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
...
Pressure vessels and the piping industry
AWS and CSA

3. A 10 minute cycle of welding time vs cooling time a given machine can handle.
...
Duty cycle
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced

4. What power sources are used with the GMAW Process?
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
Short- circuiting transfer - Globular transfer - Spray transfer

5. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)
Spatter problems and poor weld appearance
Puddle fluidity

6. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
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
5.8 to 12.5 L/min
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

7. What wire are knurled drive rolls most commonly used on?
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas
Flux cored wires
National Electrical Manufactures Association

8. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
National Electrical Manufactures Association
Pressure - The rate of flow of a shielding gas
12 to 22 arc volts

9. Give a description of 'pinch effect'
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

10. What output on the welding machine is used to rate the duty cycle?
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or 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
Minutes of elapsed time continually run (out of 10 minutes)

11. What processes are constant current (CC) power sources designed to be used with?
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW
Gives arc voltage values to the control system of the feeder

12. What are the 2 types of wire feeders available?
Duty cycle
National Electrical Manufactures Association
Speed of the feed motor and - starting / stopping electrode feed
Constant- speed wire feeders and Voltage- sennsing wire feeders

13. What does the wire feeder control?
Puddle fluidity
Speed of the feed motor and - starting / stopping electrode feed
Penetration and burn - off rate of the electrode
...

14. In the GMAW process what does amperage control?
Welding process that joins metals by heating them with an electric arc
85%
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode

15. What is an advantage of pulsed arc transfer with GMAW?
AWS and CSA
Gives arc voltage values to the control system of the feeder
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Aluminum wire

16. List 3 forms compressed gases may be supplied for welding
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
...
(DCEP) Direct Current Electrode Positive or Reverse polarity

17. What does inductance control?
Generally not as accurate
Minimum distortion due to low heat input
The time rate of response for the current rise and fall
When the filler wire is in direct contract with the base metal

18. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Guns
...
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

19. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
If you dont know this check your phone

20. What 2 controls are found on a GMAW set- up?
15 feet (4.5 meters)
20 to 200 times per second
Wire feed speed - Voltage control
Short- circuiting transfer - Globular transfer - Spray transfer

21. List several industries that would use 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
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry

22. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Penetration and burn - off rate of the electrode
Puddle fluidity
Generally not as accurate
Welding process that joins metals by heating them with an electric arc

23. Regulators control_____________ flowmeters SHOW____________.
Aluminum wire
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas

24. What current and polarity is generally used with GMAW?
Flux cored wires
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
The negative side of a welding unit

25. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
Aluminum wire

26. What type of power source is used with a constant speed wire feeder?
Aluminum wire
Constant voltage (CV)
Puddle fluidity
1/4 inch to 1/2 inch

27. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch
Insufficient current to melt the wire off cleanly

28. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove

29. What 2 organizations designate specifications for GMAW wires?
Generally not as accurate
These terms are quite restrictive and often technically incorrect
AWS and CSA
Spatter problems and poor weld appearance

30. What is the preferred drive roll design for solid wires?
Short- circuiting transfer - Globular transfer - Spray transfer
V groove or U groove
Generally not as accurate
These terms are quite restrictive and often technically incorrect

31. List the basic equipment requirements for the GMAW process
Pressure vessels and the piping industry
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
Penetration and burn - off rate of the electrode

32. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube
The resistace to electrical current flow increases with it. Causing the electrode to heat
The time rate of response for the current rise and fall

33. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Welding process that joins metals by heating them with an electric arc
Spatter problems and poor weld appearance
The negative side of a welding unit

34. What would be an indication that the drive roll pressure is adjusted correctly?
Puddle fluidity
Aluminum wire
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

35. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Flux cored wires
Wire feed speed - Voltage control
3
These terms are quite restrictive and often technically incorrect

36. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Higher 26 to 35 arc volts
Wire feed speed - Voltage control
Flux cored wires

37. What is another term for electrode holders for GMAW?
Guns
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

38. List the factors that determine the mode of metal transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas
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
Minutes of elapsed time continually run (out of 10 minutes)

39. What does the term GMAW identify?
Gas metal arc welding
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
Pressure - The rate of flow of a shielding gas

40. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%
Wire feed speed
SMAW - GTAW

41. A pull type drive system is usually used on what type of material?
Penetration and burn - off rate of the electrode
Aluminum wire
Generally not as accurate
When the filler wire is in direct contract with the base metal

42. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed

43. What is the maximum distance that hard wire can be successfully pushed?
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs

44. What is a solenoid valve and what actuates it?
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
If you dont know this check your phone
Minimum distortion due to low heat input

45. What is the effect of too much slope?
1/4 inch to 1/2 inch
...
Insufficient current to melt the wire off cleanly
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

46. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc

47. What controls amperage when using GMAW?
The negative side of a welding unit
Wire feed speed
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)

48. What is the main purpose of 'slope'?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer

49. Draw a typical volt amp curve for a machine that is designed for GMAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant voltage (CV)
Aluminum wire
If you dont know this check your phone

50. What is the required arc voltage used for short circuit transfer?
Penetration and burn - off rate of the electrode
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts
Duty cycle