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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. List several industries that would use GMAW
Higher 26 to 35 arc volts
Pressure vessels and the piping industry
Speed of the feed motor and - starting / stopping electrode feed
Dry ice can form within the flow control openings and cause blockage of shielding gas

2. What does the wire feeder control?
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed
The time rate of response for the current rise and fall

3. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
3
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

4. What controls the wire speed on a voltage sensing wire feeder?
Pressure vessels and the piping industry
The Arc voltage
Shielding the molten weld metal from atmospheric contamination
Duty cycle

5. What processes are constant current (CC) power sources designed to be used with?
Minimum distortion due to low heat input
Constant voltage (CV)
SMAW - GTAW
To prevent drawing of liquid CO2 (Carbon Dioxide)

6. In the GMAW process what does amperage control?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Minimum distortion due to low heat input
The negative side of a welding unit
Penetration and burn - off rate of the electrode

7. What is the maximum distance that hard wire can be successfully pushed?
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
15 feet (4.5 meters)
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)

8. What does the term GMAW identify?
Motor driven generators - Transformer rectifiers - and Inverter designs
Gas metal arc welding
...
SMAW - GTAW

9. Give a description of 'pinch effect'
Motor driven generators - Transformer rectifiers - and Inverter designs
The negative side of a welding unit
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly

10. How many times per second does short circuiting take place?
20 to 200 times per second
Constant current (CC)
The negative side of a welding unit
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

11. What is a solenoid valve and what actuates it?
...
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To prevent leakage - Carbon Dioxide (CO2)
Cause flaking - which can clog the liner and contact tube

12. Draw a typical volt amp curve for a machine that is designed for GMAW
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

13. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
Duty cycle

14. Why is the term GMAW preferred over MIG or MAG?
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
These terms are quite restrictive and often technically incorrect

15. Why must CO2 cylinders be used in the vertical position?
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode

16. How are GMAW guns rated?
The negative side of a welding unit
By there current carrying capacity
SMAW - GTAW
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

17. What is the main purpose of 'slope'?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced
Aluminum wire

18. Why is a line heater required when using GMAW?
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed - Voltage control
Dry ice can form within the flow control openings and cause blockage of shielding gas

19. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
Dry ice can form within the flow control openings and cause blockage of shielding gas
3

20. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
V groove or U groove
The time rate of response for the current rise and fall
Higher 26 to 35 arc volts
These terms are quite restrictive and often technically incorrect

21. What is the purpose of a regulator and what does it indicate on its gauges?
AWS and CSA
85%
Reducing the gas source pressure to a constant working pressure
Constant voltage (CV)

22. List 3 forms compressed gases may be supplied for welding
Gives arc voltage values to the control system of the feeder
Penetration and burn - off rate of the electrode
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

23. What wire are knurled drive rolls most commonly used on?
5.8 to 12.5 L/min
Constant current (CC)
Spatter problems and poor weld appearance
Flux cored wires

24. A 10 minute cycle of welding time vs cooling time a given machine can handle.
If you dont know this check your phone
Duty cycle
Higher 26 to 35 arc volts
By there current carrying capacity

25. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Cause flaking - which can clog the liner and contact tube
3
Duty cycle
Penetration and burn - off rate of the electrode

26. What is the key advantage of short circuiting transfer?
Wire feed speed
Minimum distortion due to low heat input
Constant voltage (CV)
3

27. What power sources are used with the GMAW Process?
Puddle fluidity
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
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs

28. Give a brief description of the GMAW process
Puddle fluidity
3
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

29. What is the recommended electrode stick- out for .035 solid wire?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination
1/4 inch to 1/2 inch

30. What type of power source is used with a constant speed wire feeder?
AWS and CSA
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity
Constant voltage (CV)

31. What current and polarity is generally used with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity

32. List 3 wire drive systems and give a short description of each
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
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
(DCEP) Direct Current Electrode Positive or Reverse polarity

33. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
If you dont know this check your phone
Generally not as accurate
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

34. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Wire feed speed
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced

35. List the three methods of metal transfer with GMAW
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant- speed wire feeders and Voltage- sennsing wire feeders

36. With straight polarity where is 2/3 of the arc energy?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Welding process that joins metals by heating them with an electric arc
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit

37. List the factors that determine the mode of metal transfer
Shielding the molten weld metal from atmospheric contamination
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Higher 26 to 35 arc volts

38. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Voltage is the force that overcomes resistance to allow amperage flow

39. In the GMAW process what does voltage control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube

40. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
AWS and CSA
Cause flaking - which can clog the liner and contact tube
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

41. What controls amperage when using GMAW?
Pressure - The rate of flow of a shielding gas
Wire feed speed
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc

42. 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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Penetration and burn - off rate of the electrode

43. What would be an indication that the drive roll pressure is adjusted correctly?
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)

44. 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
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
By there current carrying capacity
Gas metal arc welding

45. What is the effect of too much slope?
Constant current (CC)
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly
Spatter problems and poor weld appearance

46. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
If you dont know this check your phone
...
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly

47. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
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
AWS and CSA

48. List the basic equipment requirements for the GMAW process
Minimum distortion due to low heat input
Gas metal arc welding
Voltage is the force that overcomes resistance to allow amperage flow
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

49. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate

50. What is a typical flow rate of CO2 for short circuit transfer?
Gas metal arc welding
5.8 to 12.5 L/min
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground