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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 is a line heater required when using GMAW?
Pressure vessels and the piping industry
Guns
The resistace to electrical current flow increases with it. Causing the electrode to heat
Dry ice can form within the flow control openings and cause blockage of shielding gas

2. What is the purpose of a regulator and what does it indicate on its gauges?
Constant current (CC)
Reducing the gas source pressure to a constant working pressure
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

3. What processes are constant current (CC) power sources designed to be used with?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
When the filler wire is in direct contract with the base metal
SMAW - GTAW

4. What current and polarity is generally used with GMAW?
Penetration and burn - off rate of the electrode
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity
These terms are quite restrictive and often technically incorrect

5. List 3 forms compressed gases may be supplied for welding
To prevent leakage - Carbon Dioxide (CO2)
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
Aluminum wire

6. List 3 wire drive systems and give a short description of each
Constant- speed wire feeders and Voltage- sennsing wire feeders
Controls the rate of flow of a shielding gas to the gun nozzle
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

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
National Electrical Manufactures Association
Generally not as accurate
Higher 26 to 35 arc volts
...

8. In the GMAW process what does voltage control?
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feed speed - Voltage control
If you dont know this check your phone

9. When is the metal transferred with short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal
DCEP (Direct Current Electrode Positive) Reverse Polarity
Flux cored wires

10. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
1/4 inch to 1/2 inch
If you dont know this check your phone
If you dont know this check your phone

11. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow
To prevent drawing of liquid CO2 (Carbon Dioxide)

12. What is an advantage of pulsed arc transfer with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure vessels and the piping industry
85%
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

13. What effect does increasing and decreasing the inductance have on the weld?
Puddle fluidity
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
Reducing the gas source pressure to a constant working pressure

14. What is a solenoid valve and what actuates it?
To limit the short circuiting current so that spatter is reduced
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
By there current carrying capacity
Constant current (CC)

15. What are the 2 types of wire feeders available?
Constant voltage (CV)
Constant- speed wire feeders and Voltage- sennsing wire feeders
These terms are quite restrictive and often technically incorrect
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

16. What wire are knurled drive rolls most commonly used on?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Duty cycle
15 feet (4.5 meters)
Flux cored wires

17. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
Generally not as accurate
If you dont know this check your phone

18. What is another term for electrode holders for GMAW?
The negative side of a welding unit
AWS and CSA
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Guns

19. How are GMAW guns rated?
Wire feed speed
By there current carrying capacity
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube

20. With straight polarity where is 2/3 of the arc energy?
If you dont know this check your phone
20 to 200 times per second
The negative side of a welding unit
AWS and CSA

21. What 2 controls are found on a GMAW set- up?
V groove or U groove
Constant current (CC)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed - Voltage control

22. What is the main purpose of 'slope'?
Duty cycle
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding
Voltage is the force that overcomes resistance to allow amperage flow

23. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Constant current (CC)
V groove or U groove
Short- circuiting transfer - Globular transfer - Spray transfer

24. What happens when the electrode extension is increased?
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed
Voltage is the force that overcomes resistance to allow amperage flow
The resistace to electrical current flow increases with it. Causing the electrode to heat

25. What is the key advantage of short circuiting transfer?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

26. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
The negative side of a welding unit
If you dont know this check your phone

27. Why is a fiber washer required and what cylinder gas requires it?
Controls the rate of flow of a shielding gas to the gun nozzle
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc

28. What does voltage do in an electrical circuit?
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle

29. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
Duty cycle

30. List the factors that determine the mode of metal transfer
By there current carrying capacity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The Arc voltage
Minimum distortion due to low heat input

31. List several industries that would use GMAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
V groove or U groove
Pressure vessels and the piping industry
Higher 26 to 35 arc volts

32. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Gas metal arc welding
Higher 26 to 35 arc volts
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc

33. Draw a typical volt amp curve for a machine that is designed for GMAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone
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

34. What is the preferred drive roll design for solid wires?
AWS and CSA
Welding process that joins metals by heating them with an electric arc
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove

35. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Aluminum wire
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)
Flux cored wires

36. What does the abbreviation NEMA stand for?
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association
Generally not as accurate
20 to 200 times per second

37. How many times per second does short circuiting take place?
The resistace to electrical current flow increases with it. Causing the electrode to heat
By there current carrying capacity
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

38. What does inductance control?
Insufficient current to melt the wire off cleanly
20 to 200 times per second
AWS and CSA
The time rate of response for the current rise and fall

39. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
Flux cored wires

40. What does the term GMAW identify?
Puddle fluidity
Wire feed speed - Voltage control
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding

41. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
12 to 22 arc volts
Flux cored wires
(DCEP) Direct Current Electrode Positive or Reverse polarity

42. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity

43. 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)
Puddle fluidity
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube

44. Regulators control_____________ flowmeters SHOW____________.
Gives arc voltage values to the control system of the feeder
Guns
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

45. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Duty cycle
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%

46. A pull type drive system is usually used on what type of material?
Aluminum wire
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Generally not as accurate

47. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
3
Penetration and burn - off rate of the electrode
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

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

49. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)
Generally not as accurate
These terms are quite restrictive and often technically incorrect

50. What 2 organizations designate specifications for GMAW wires?
Wire feed speed - Voltage control
Pressure vessels and the piping industry
Duty cycle
AWS and CSA