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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.
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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 purpose of the pick- up lead on a voltage sensing wire feeder?
V groove or U groove
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
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gives arc voltage values to the control system of the feeder

2. What 2 controls are found on a GMAW set- up?
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced

3. What is the main purpose of 'slope'?
Gas metal arc welding
Gives arc voltage values to the control system of the feeder
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

4. What is the maximum distance that hard wire can be successfully pushed?
Gives arc voltage values to the control system of the feeder
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)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

5. What type of power source is commonly used with a voltage sensing wire feeder?
15 feet (4.5 meters)
Constant current (CC)
The time rate of response for the current rise and fall
Higher 26 to 35 arc volts

6. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)
85%
20 to 200 times per second

7. What is the purpose of a regulator and what does it indicate on its gauges?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Reducing the gas source pressure to a constant working pressure

8. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
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
V groove or U groove

9. In the GMAW process what does voltage control?
Minutes of elapsed time continually run (out of 10 minutes)
Aluminum wire
Puddle fluidity
20 to 200 times per second

10. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Short- circuiting transfer - Globular transfer - Spray transfer
Puddle fluidity
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

11. Why must CO2 cylinders be used in the vertical position?
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle

12. What is another term for electrode holders for GMAW?
Constant current (CC)
3
The negative side of a welding unit
Guns

13. What type of power source is used with a constant speed wire feeder?
Wire feed speed
If you dont know this check your phone
Constant voltage (CV)
Shielding the molten weld metal from atmospheric contamination

14. 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
V groove or U groove
Gives arc voltage values to the control system of the feeder
Constant current (CC)

15. What output on the welding machine is used to rate the duty cycle?
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)

16. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder
Aluminum wire
AWS and CSA

17. How are GMAW guns rated?
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance
By there current carrying capacity
Pressure vessels and the piping industry

18. List several industries that would use GMAW
Shielding the molten weld metal from atmospheric contamination
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode
If you dont know this check your phone

19. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Reducing the gas source pressure to a constant working pressure
AWS and CSA
15 feet (4.5 meters)

20. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Speed of the feed motor and - starting / stopping electrode feed
To limit the short circuiting current so that spatter is reduced

21. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
Aluminum wire
20 to 200 times per second
Pressure vessels and the piping industry

22. What current and polarity is generally used with GMAW?
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly
DCEP (Direct Current Electrode Positive) Reverse Polarity

23. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)

24. List the basic equipment requirements for the GMAW process
Minimum distortion due to low heat input
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Guns

25. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
If you dont know this check your phone
V groove or U groove
To prevent leakage - Carbon Dioxide (CO2)

26. What effect does increasing and decreasing the inductance have on the weld?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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 prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)

27. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Speed of the feed motor and - starting / stopping electrode feed
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
By there current carrying capacity

28. Why is a fiber washer required and what cylinder gas requires it?
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent leakage - Carbon Dioxide (CO2)

29. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

30. Why is a line heater required when using GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas
Reducing the gas source pressure to a constant working pressure

31. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Gas metal arc welding
Penetration and burn - off rate of the electrode
The time rate of response for the current rise and fall

32. When is the metal transferred with short circuit transfer?
Flux cored wires
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
When the filler wire is in direct contract with the base metal

33. What does the term GMAW identify?
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
Gas metal arc welding

34. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
Dry ice can form within the flow control openings and cause blockage of shielding gas
Duty cycle

35. 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)
Minimum distortion due to low heat input
By there current carrying capacity
Pressure vessels and the piping industry

36. What does a flowmeter do and what does it measure?
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
Guns
Constant voltage (CV)

37. What is a typical flow rate of CO2 for short circuit transfer?
If you dont know this check your phone
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns
5.8 to 12.5 L/min

38. What is the preferred drive roll design for solid wires?
20 to 200 times per second
V groove or U groove
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

39. 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
Aluminum wire
When the filler wire is in direct contract with the base metal
Minutes of elapsed time continually run (out of 10 minutes)

40. Regulators control_____________ flowmeters SHOW____________.
Insufficient current to melt the wire off cleanly
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
Pressure - The rate of flow of a shielding gas

41. List 3 wire drive systems and give a short description of each
Gas metal arc welding
Duty cycle
When the filler wire is in direct contract with the base metal
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

42. What controls amperage when using GMAW?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feed speed
Voltage is the force that overcomes resistance to allow amperage flow
Constant voltage (CV)

43. With straight polarity where is 2/3 of the arc energy?
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)
12 to 22 arc volts

44. In the GMAW process what does amperage control?
Generally not as accurate
Penetration and burn - off rate of the electrode
85%
Short- circuiting transfer - Globular transfer - Spray transfer

45. What is the purpose of the shielding gas used in GMAW?
...
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The negative side of a welding unit

46. What does inductance control?
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
Constant- speed wire feeders and Voltage- sennsing wire feeders
The time rate of response for the current rise and fall

47. How many times per second does short circuiting take place?
Gives arc voltage values to the control system of the feeder
The time rate of response for the current rise and fall
20 to 200 times per second
These terms are quite restrictive and often technically incorrect

48. What does the abbreviation NEMA stand for?
SMAW - GTAW
Aluminum wire
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association

49. What is the effect of too much slope?
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
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)

50. What is the recommended electrode stick- out for .035 solid wire?
Speed of the feed motor and - starting / stopping electrode feed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
1/4 inch to 1/2 inch
Wire feed speed - Voltage control