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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 recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry

2. What is the effect of too much slope?
Spatter problems and poor weld appearance
Flux cored wires
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer

3. What wire are knurled drive rolls most commonly used on?
Flux cored wires
3
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch

4. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Insufficient current to melt the wire off cleanly

6. Why is a fiber washer required and what cylinder gas requires it?
1/4 inch to 1/2 inch
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input

7. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Spatter problems and poor weld appearance
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder

8. Give a brief description of the GMAW process
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
Speed of the feed motor and - starting / stopping electrode feed
Welding process that joins metals by heating them with an electric arc

9. What is a solenoid valve and what actuates it?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
...
SMAW - GTAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

10. What is the key advantage of short circuiting transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity

11. What is the purpose of the shielding gas used in GMAW?
85%
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination

12. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Controls the rate of flow of a shielding gas to the gun nozzle
12 to 22 arc volts
Gives arc voltage values to the control system of the feeder
...

13. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Insufficient current to melt the wire off cleanly
Duty cycle
15 feet (4.5 meters)
3

14. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Higher 26 to 35 arc volts

15. What type of power source is commonly used with a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)
Gives arc voltage values to the control system of the feeder
Cause flaking - which can clog the liner and contact tube

16. A pull type drive system is usually used on what type of material?
1/4 inch to 1/2 inch
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire
The Arc voltage

17. In the GMAW process what does voltage control?
Speed of the feed motor and - starting / stopping electrode feed
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
Puddle fluidity

18. What is the required arc voltage used for short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
20 to 200 times per second
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

19. How many times per second does short circuiting take place?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal

20. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
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
Aluminum wire
The time rate of response for the current rise and fall

21. What does inductance control?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
Speed of the feed motor and - starting / stopping electrode feed

22. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Motor driven generators - Transformer rectifiers - and Inverter designs
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

23. What power sources are used with the GMAW Process?
The time rate of response for the current rise and fall
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
Penetration and burn - off rate of the electrode

24. What does the wire feeder control?
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

25. What are the 2 types of wire feeders available?
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
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant- speed wire feeders and Voltage- sennsing wire feeders

26. 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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity
1/4 inch to 1/2 inch

27. What current and polarity is generally used with GMAW?
Welding process that joins metals by heating them with an electric arc
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires
Constant voltage (CV)

28. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Puddle fluidity
Generally not as accurate
By there current carrying capacity

29. Why is the term GMAW preferred over MIG or MAG?
V groove or U groove
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect

30. Why must CO2 cylinders be used in the vertical position?
Welding process that joins metals by heating them with an electric arc
The Arc voltage
Wire feed speed
To prevent drawing of liquid CO2 (Carbon Dioxide)

31. What does the abbreviation NEMA stand for?
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube

32. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3
Controls the rate of flow of a shielding gas to the gun nozzle
...

33. What effect does increasing and decreasing the inductance have on the weld?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Higher 26 to 35 arc volts

34. 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)
Aluminum wire
Constant voltage (CV)
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

35. List the basic equipment requirements for the GMAW process
Insufficient current to melt the wire off cleanly
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
SMAW - GTAW

36. Draw a typical volt amp curve for a machine that is designed for GMAW
The negative side of a welding unit
Dry ice can form within the flow control openings and cause blockage of shielding gas
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

37. List 3 wire drive systems and give a short description of each
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
Aluminum wire
The time rate of response for the current rise and fall

38. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
85%

39. What is the main purpose of 'slope'?
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced
(DCEP) Direct Current Electrode Positive or Reverse polarity
3

40. What 2 controls are found on a GMAW set- up?
Penetration and burn - off rate of the electrode
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed - Voltage control
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

41. Regulators control_____________ flowmeters SHOW____________.
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas
National Electrical Manufactures Association
Dry ice can form within the flow control openings and cause blockage of shielding gas

42. What controls amperage when using GMAW?
Speed of the feed motor and - starting / stopping electrode feed
SMAW - GTAW
The time rate of response for the current rise and fall
Wire feed speed

43. What controls the wire speed on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
The Arc voltage
3
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

44. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
20 to 200 times per second
Higher 26 to 35 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association

45. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Cause flaking - which can clog the liner and contact tube

46. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
12 to 22 arc volts
Cause flaking - which can clog the liner and contact tube
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity

47. What is an advantage of pulsed arc transfer with GMAW?
Constant current (CC)
Insufficient current to melt the wire off cleanly
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

48. What does the term GMAW identify?
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced
Minimum distortion due to low heat input
Gas metal arc welding

49. Give a description of 'pinch effect'
Higher 26 to 35 arc volts
Motor driven generators - Transformer rectifiers - and Inverter designs
Gas metal arc welding
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

50. List several industries that would use GMAW
Flux cored wires
Pressure vessels and the piping industry
To prevent drawing of liquid CO2 (Carbon Dioxide)
To prevent leakage - Carbon Dioxide (CO2)