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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. 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
Wire feed speed - Voltage control
If you dont know this check your phone

2. What is the maximum distance that hard wire can be successfully pushed?
DCEP (Direct Current Electrode Positive) Reverse Polarity
...
Cause flaking - which can clog the liner and contact tube
15 feet (4.5 meters)

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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
The time rate of response for the current rise and fall
If you dont know this check your phone

4. Why is a line heater required when using GMAW?
Guns
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect
Aluminum wire

5. A pull type drive system is usually used on what type of material?
Aluminum wire
Flux cored wires
Higher 26 to 35 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

6. Regulators control_____________ flowmeters SHOW____________.
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
Constant voltage (CV)
The negative side of a welding unit

7. In the GMAW process what does voltage control?
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
Puddle fluidity

8. What effect does increasing and decreasing the inductance have on 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
12 to 22 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Reducing the gas source pressure to a constant working pressure

9. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
National Electrical Manufactures Association
20 to 200 times per second
Wire feed speed
Cause flaking - which can clog the liner and contact tube

10. What does voltage do in an electrical circuit?
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
To prevent leakage - Carbon Dioxide (CO2)

11. What is another term for electrode holders for GMAW?
1/4 inch to 1/2 inch
Guns
Minutes of elapsed time continually run (out of 10 minutes)
The Arc voltage

12. Why must CO2 cylinders be used in the vertical position?
These terms are quite restrictive and often technically incorrect
Guns
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)

13. What is an advantage of pulsed arc transfer with GMAW?
Penetration and burn - off rate of the electrode
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

14. Why is the term GMAW preferred over MIG or MAG?
Penetration and burn - off rate of the electrode
These terms are quite restrictive and often technically incorrect
V groove or U groove
The time rate of response for the current rise and fall

15. In the GMAW process what does amperage control?
National Electrical Manufactures Association
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Penetration and burn - off rate of the electrode
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

16. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Penetration and burn - off rate of the electrode
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders

17. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
Gives arc voltage values to the control system of the feeder
National Electrical Manufactures Association

18. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
85%
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. What is the recommended electrode stick- out for .035 solid wire?
Minimum distortion due to low heat input
The negative side of a welding unit
1/4 inch to 1/2 inch
Gas metal arc welding

20. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Constant voltage (CV)
Wire feed speed - Voltage control
Voltage is the force that overcomes resistance to allow amperage flow

21. Why is a fiber washer required and what cylinder gas requires it?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Controls the rate of flow of a shielding gas to the gun nozzle

22. What is the purpose of the shielding gas used in GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
Higher 26 to 35 arc volts

23. What type of power source is used with a constant speed wire feeder?
Reducing the gas source pressure to a constant working pressure
Constant voltage (CV)
The negative side of a welding unit
The resistace to electrical current flow increases with it. Causing the electrode to heat

24. What does inductance control?
The time rate of response for the current rise and fall
By there current carrying capacity
Guns
85%

25. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Flux cored wires
Constant current (CC)
Aluminum wire

26. What processes are constant current (CC) power sources designed to be used with?
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW
Voltage is the force that overcomes resistance to allow amperage flow
Insufficient current to melt the wire off cleanly

27. How are GMAW guns rated?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow
Generally not as accurate
By there current carrying capacity

28. What does the term GMAW identify?
Duty cycle
Guns
20 to 200 times per second
Gas metal arc welding

29. What 2 organizations designate specifications for GMAW wires?
Pressure vessels and the piping industry
AWS and CSA
If you dont know this check your phone
Higher 26 to 35 arc volts

30. Give a description of 'pinch effect'
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Pressure vessels and the piping industry

31. What is the effect of too much slope?
Controls the rate of flow of a shielding gas to the gun nozzle
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall
Guns

32. What controls amperage when using GMAW?
Penetration and burn - off rate of the electrode
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer
DCEP (Direct Current Electrode Positive) Reverse Polarity

33. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
15 feet (4.5 meters)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

34. What would be an indication that the drive roll pressure is adjusted correctly?
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure vessels and the piping industry
Wire feeds smoothly (yet will slip should a problem occur in the gun)

35. What wire are knurled drive rolls most commonly used on?
Pressure - The rate of flow of a shielding gas
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
20 to 200 times per second
Flux cored wires

36. When is the metal transferred with short circuit transfer?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
When the filler wire is in direct contract with the base metal

37. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed

38. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Speed of the feed motor and - starting / stopping electrode feed
Controls the rate of flow of a shielding gas to the gun nozzle

39. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
85%
20 to 200 times per second
Constant voltage (CV)

40. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
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
Shielding the molten weld metal from atmospheric contamination

41. What is the main purpose of 'slope'?
Cause flaking - which can clog the liner and contact tube
85%
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)

42. What is the purpose of a regulator and what does it indicate on its gauges?
...
Reducing the gas source pressure to a constant working pressure
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Wire feeds smoothly (yet will slip should a problem occur in the gun)

43. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3
By there current carrying capacity
V groove or U groove

44. List 3 wire drive systems and give a short description of each
Higher 26 to 35 arc volts
3
20 to 200 times per second
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

45. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Speed of the feed motor and - starting / stopping electrode feed
Constant current (CC)
Guns

46. What is the preferred drive roll design for solid wires?
The negative side of a welding unit
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
Speed of the feed motor and - starting / stopping electrode feed

47. What is a typical flow rate of CO2 for short circuit transfer?
Welding process that joins metals by heating them with an electric arc
Pressure vessels and the piping industry
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat

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

49. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

50. What does the wire feeder control?
3
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%