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Test your basic knowledge |

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 controls amperage when using GMAW?
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
The negative side of a welding unit

2. 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
Generally not as accurate
Constant voltage (CV)
SMAW - GTAW

3. Why is globular transfer generally avoided with GMAW?
1/4 inch to 1/2 inch
Constant voltage (CV)
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance

4. What happens when the electrode extension is increased?
Wire feed speed - Voltage control
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure

5. What type of power source is used with a constant speed wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)
Insufficient current to melt the wire off cleanly
...

6. What 2 organizations designate specifications for GMAW wires?
Constant current (CC)
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage

7. 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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...
To limit the short circuiting current so that spatter is reduced

8. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

9. Draw a typical volt amp curve for a machine that is designed for GMAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed
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By there current carrying capacity

10. List 3 forms compressed gases may be supplied for welding
...
Gives arc voltage values to the control system of the feeder
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Voltage is the force that overcomes resistance to allow amperage flow

11. What is the recommended electrode stick- out for .035 solid wire?
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry

12. What processes are constant current (CC) power sources designed to be used with?
The Arc voltage
1/4 inch to 1/2 inch
SMAW - GTAW
85%

13. Regulators control_____________ flowmeters SHOW____________.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The time rate of response for the current rise and fall
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas

14. What controls the wire speed on a voltage sensing wire feeder?
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat
The Arc voltage
Puddle fluidity

15. What output on the welding machine is used to rate the duty cycle?
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)
Motor driven generators - Transformer rectifiers - and Inverter designs

16. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Puddle fluidity
85%
1/4 inch to 1/2 inch

17. How are GMAW guns rated?
Pressure vessels and the piping industry
Minimum distortion due to low heat input
If you dont know this check your phone
By there current carrying capacity

18. What does inductance control?
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall

19. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

20. What 2 controls are found on a GMAW set- up?
Generally not as accurate
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

21. Why is the term GMAW preferred over MIG or MAG?
Short- circuiting transfer - Globular transfer - Spray transfer
Gas metal arc welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect

22. In the GMAW process what does voltage control?
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer
Higher 26 to 35 arc volts
Puddle fluidity

23. What does voltage do in an electrical circuit?
1/4 inch to 1/2 inch
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal

24. What is a solenoid valve and what actuates it?
Constant voltage (CV)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Shielding the molten weld metal from atmospheric contamination
National Electrical Manufactures Association

25. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input
Wire feeds smoothly (yet will slip should a problem occur in the gun)

26. What is the required arc voltage used for short circuit transfer?
Constant voltage (CV)
12 to 22 arc volts
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly

27. With straight polarity where is 2/3 of the arc energy?
SMAW - GTAW
The negative side of a welding unit
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns

28. What is the maximum distance that hard wire can be successfully pushed?
Constant current (CC)
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
...

29. What is the effect of too much slope?
3
Guns
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

30. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
...

31. What does a flowmeter do and what does it measure?
The negative side of a welding unit
Controls the rate of flow of a shielding gas to the gun nozzle
Constant- speed wire feeders and Voltage- sennsing wire feeders
20 to 200 times per second

32. What current and polarity is generally used with GMAW?
Generally not as accurate
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
DCEP (Direct Current Electrode Positive) Reverse Polarity

33. What wire are knurled drive rolls most commonly used on?
85%
5.8 to 12.5 L/min
Flux cored wires
If you dont know this check your phone

34. List several industries that would use GMAW
Pressure vessels and the piping industry
V groove or U groove
Motor driven generators - Transformer rectifiers - and Inverter designs
Guns

35. What is the preferred drive roll design for solid wires?
Constant current (CC)
Spatter problems and poor weld appearance
20 to 200 times per second
V groove or U groove

36. What does the term GMAW identify?
Duty cycle
Gas metal arc welding
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

37. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed
DCEP (Direct Current Electrode Positive) Reverse Polarity

38. What is the main purpose of 'slope'?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc
To limit the short circuiting current so that spatter is reduced
DCEP (Direct Current Electrode Positive) Reverse Polarity

39. What is another term for electrode holders for GMAW?
Guns
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance
5.8 to 12.5 L/min

40. What is a typical flow rate of CO2 for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
5.8 to 12.5 L/min
...
Reducing the gas source pressure to a constant working pressure

41. How many times per second does short circuiting take place?
20 to 200 times per second
By there current carrying capacity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

42. List the factors that determine the mode of metal transfer
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
To prevent leakage - Carbon Dioxide (CO2)
Generally not as accurate

43. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The resistace to electrical current flow increases with it. Causing the electrode to heat
V groove or U groove
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3

44. A 10 minute cycle of welding time vs cooling time a given machine can handle.
SMAW - GTAW
Duty cycle
If you dont know this check your phone
Wire feeds smoothly (yet will slip should a problem occur in the gun)

45. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Minimum distortion due to low heat input

46. A pull type drive system is usually used on what type of material?
...
Aluminum wire
DCEP (Direct Current Electrode Positive) Reverse Polarity
When the filler wire is in direct contract with the base metal

47. What type of power source is commonly used with a voltage sensing wire feeder?
Flux cored wires
Constant current (CC)
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control

48. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Penetration and burn - off rate of the electrode
Shielding the molten weld metal from atmospheric contamination
Generally not as accurate
Aluminum wire

49. List 3 wire drive systems and give a short description of each
SMAW - GTAW
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
If you dont know this check your phone
The resistace to electrical current flow increases with it. Causing the electrode to heat

50. When is the metal transferred with short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant voltage (CV)
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced