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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 preferred drive roll design for solid wires?
V groove or U groove
AWS and CSA
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)

2. What is the purpose of a regulator and what does it indicate on its gauges?
Constant current (CC)
If you dont know this check your phone
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure

3. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Voltage is the force that overcomes resistance to allow amperage flow
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
12 to 22 arc volts
SMAW - GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat

5. Why must CO2 cylinders be used in the vertical position?
Wire feed speed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)

6. What wire are knurled drive rolls most commonly used on?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
Minimum distortion due to low heat input

7. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Pressure vessels and the piping industry
Higher 26 to 35 arc volts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feed speed - Voltage control

8. What does the term GMAW identify?
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs
Gas metal arc welding
To limit the short circuiting current so that spatter is reduced

9. Why is a line heater required when using GMAW?
By there current carrying capacity
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input

10. List the basic equipment requirements for the GMAW process
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall

11. What does the abbreviation NEMA stand for?
12 to 22 arc volts
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
Welding process that joins metals by heating them with an electric arc

12. Why is the term GMAW preferred over MIG or MAG?
The time rate of response for the current rise and fall
Gives arc voltage values to the control system of the feeder
Constant voltage (CV)
These terms are quite restrictive and often technically incorrect

13. In the GMAW process what does voltage control?
Puddle fluidity
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer
Dry ice can form within the flow control openings and cause blockage of shielding gas

14. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance

15. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
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
Gas metal arc welding

16. What are the 2 types of wire feeders available?
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

17. What is the recommended electrode stick- out for .035 solid wire?
12 to 22 arc volts
The Arc voltage
1/4 inch to 1/2 inch
Duty cycle

18. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minimum distortion due to low heat input

19. A pull type drive system is usually used on what type of material?
Generally not as accurate
V groove or U groove
Constant voltage (CV)
Aluminum wire

20. What does inductance control?
AWS and CSA
The time rate of response for the current rise and fall
Duty cycle
...

21. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
The negative side of a welding unit
Constant current (CC)
SMAW - GTAW

22. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
The negative side of a welding unit
Gas metal arc welding
...
Cause flaking - which can clog the liner and contact tube

23. What controls amperage when using GMAW?
5.8 to 12.5 L/min
Reducing the gas source pressure to a constant working pressure
V groove or U groove
Wire feed speed

24. What controls the wire speed on a voltage sensing wire feeder?
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
The Arc voltage
SMAW - GTAW

25. What is a solenoid valve and what actuates it?
5.8 to 12.5 L/min
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The negative side of a welding unit

26. What 2 controls are found on a GMAW set- up?
Insufficient current to melt the wire off cleanly
3
Duty cycle
Wire feed speed - Voltage control

27. What type of power source is commonly used with a voltage sensing wire feeder?
SMAW - GTAW
When the filler wire is in direct contract with the base metal
20 to 200 times per second
Constant current (CC)

28. With straight polarity where is 2/3 of the arc energy?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder
Guns
The negative side of a welding unit

29. What power sources are used with the GMAW Process?
20 to 200 times per second
Motor driven generators - Transformer rectifiers - and Inverter designs
Guns
Penetration and burn - off rate of the electrode

30. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
AWS and CSA
Generally not as accurate

31. What is the required arc voltage used for short circuit transfer?
Welding process that joins metals by heating them with an electric arc
V groove or U groove
12 to 22 arc volts
3

32. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
3

33. Give a brief description of the GMAW process
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Voltage is the force that overcomes resistance to allow amperage flow
Welding process that joins metals by heating them with an electric arc
Motor driven generators - Transformer rectifiers - and Inverter designs

34. How many times per second does short circuiting take place?
1/4 inch to 1/2 inch
20 to 200 times per second
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

35. What is the effect of too much slope?
V groove or U groove
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal
3

36. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect

37. What does the wire feeder control?
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
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Speed of the feed motor and - starting / stopping electrode feed

38. Why is a fiber washer required and what cylinder gas requires it?
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
Minimum distortion due to low heat input
Guns

39. What is the key advantage of short circuiting transfer?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
By there current carrying capacity
SMAW - GTAW
Minimum distortion due to low heat input

40. What is a typical flow rate of CO2 for short circuit transfer?
The time rate of response for the current rise and fall
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
Aluminum wire

41. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
By there current carrying capacity
If you dont know this check your phone
Generally not as accurate
These terms are quite restrictive and often technically incorrect

42. What does voltage do in an electrical circuit?
Duty cycle
Voltage is the force that overcomes resistance to allow amperage flow
3
Spatter problems and poor weld appearance

43. List the factors that determine the mode of metal transfer
Wire feed speed
85%
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Dry ice can form within the flow control openings and cause blockage of shielding gas

44. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant current (CC)
To limit the short circuiting current so that spatter is reduced
1/4 inch to 1/2 inch

45. What effect does increasing and decreasing the inductance have on the weld?
Gas metal arc welding
Aluminum wire
Gives arc voltage values to the control system of the feeder
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. List several industries that would use GMAW
Pressure - The rate of flow of a shielding gas
Pressure vessels and the piping industry
To limit the short circuiting current so that spatter is reduced
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

47. What 2 organizations designate specifications for GMAW wires?
The Arc voltage
Spatter problems and poor weld appearance
AWS and CSA
Generally not as accurate

48. Why is globular transfer generally avoided 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
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)

49. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure
Short- circuiting transfer - Globular transfer - Spray transfer

50. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal