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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 reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
By there current carrying capacity
...
Guns
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2. What is the recommended electrode stick- out for .035 solid wire?
SMAW - GTAW
Welding process that joins metals by heating them with an electric arc
By there current carrying capacity
1/4 inch to 1/2 inch

3. In the GMAW process what does voltage control?
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts

4. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Pressure vessels and the piping industry
Generally not as accurate
Cause flaking - which can clog the liner and contact tube
Insufficient current to melt the wire off cleanly

5. What 2 controls are found on a GMAW set- up?
Constant voltage (CV)
3
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control

6. Give a description of 'pinch effect'
Welding process that joins metals by heating them with an electric arc
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To limit the short circuiting current so that spatter is reduced

7. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal
3

8. Why is globular transfer generally avoided with GMAW?
These terms are quite restrictive and often technically incorrect
Spatter problems and poor weld appearance
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When the filler wire is in direct contract with the base metal

9. What controls the wire speed on a voltage sensing wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage
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

10. What does the term GMAW identify?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding
Welding process that joins metals by heating them with an electric arc
AWS and CSA

11. Why is a line heater required when using GMAW?
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders

12. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
SMAW - GTAW
20 to 200 times per second
Pressure vessels and the piping industry

13. What is a solenoid valve and what actuates it?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed

14. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Gas metal arc welding
When the filler wire is in direct contract with the base metal
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15. List 3 forms compressed gases may be supplied for welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

16. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Spatter problems and poor weld appearance
Gives arc voltage values to the control system of the feeder

17. What is an advantage of pulsed arc transfer with GMAW?
To limit the short circuiting current so that spatter is reduced
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Cause flaking - which can clog the liner and contact tube
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

18. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
...

19. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
12 to 22 arc volts

20. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer

21. What output on the welding machine is used to rate the duty cycle?
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%

22. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
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(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

23. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Minutes of elapsed time continually run (out of 10 minutes)
Cause flaking - which can clog the liner and contact tube
DCEP (Direct Current Electrode Positive) Reverse Polarity
V groove or U groove

24. What is a typical flow rate of CO2 for short circuit transfer?
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall
1/4 inch to 1/2 inch
5.8 to 12.5 L/min

25. 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)
85%
...
Short- circuiting transfer - Globular transfer - Spray transfer

26. What would be an indication that the drive roll pressure is adjusted correctly?
Higher 26 to 35 arc volts
Aluminum wire
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts

27. How are GMAW guns rated?
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
By there current carrying capacity
Shielding the molten weld metal from atmospheric contamination
Duty cycle

28. What does the abbreviation NEMA stand for?
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 Arc voltage
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal

29. List 3 wire drive systems and give a short description of each
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...

30. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Generally not as accurate
Wire feed speed - Voltage control
Duty cycle
85%

31. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas

32. How many times per second does short circuiting take place?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second
(DCEP) Direct Current Electrode Positive or Reverse polarity

33. What 2 organizations designate specifications for GMAW wires?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed
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

34. Draw a typical volt amp curve for a machine that is designed for GMAW
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Controls the rate of flow of a shielding gas to the gun nozzle
...
Aluminum wire

35. List several industries that would use GMAW
Constant current (CC)
20 to 200 times per second
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure vessels and the piping industry

36. What processes are constant current (CC) power sources designed to be used with?
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
SMAW - GTAW
5.8 to 12.5 L/min

37. A pull type drive system is usually used on what type of material?
Constant voltage (CV)
Penetration and burn - off rate of the electrode
Generally not as accurate
Aluminum wire

38. List the basic equipment requirements for the GMAW process
To limit the short circuiting current so that spatter is reduced
Puddle fluidity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The Arc voltage

39. What is another term for electrode holders for GMAW?
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat
Guns

40. What are the 2 types of wire feeders available?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
...
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns

41. What type of power source is used with a constant speed wire feeder?
12 to 22 arc volts
Constant voltage (CV)
Short- circuiting transfer - Globular transfer - Spray transfer
Penetration and burn - off rate of the electrode

42. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Shielding the molten weld metal from atmospheric contamination
By there current carrying capacity
Speed of the feed motor and - starting / stopping electrode feed

43. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
...
5.8 to 12.5 L/min
Minutes of elapsed time continually run (out of 10 minutes)

44. 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
DCEP (Direct Current Electrode Positive) Reverse Polarity
SMAW - GTAW
The time rate of response for the current rise and fall

45. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow
AWS and CSA

46. What current and polarity is generally used with GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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
Gas metal arc welding

47. Why is a fiber washer required and what cylinder gas requires it?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
Generally not as accurate

48. List the three methods of metal transfer with GMAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube

49. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding

50. What is the key advantage of short circuiting transfer?
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity
...
Minimum distortion due to low heat input