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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 2 organizations designate specifications for GMAW wires?
Motor driven generators - Transformer rectifiers - and Inverter designs
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
AWS and CSA

2. What controls the wire speed on a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The Arc voltage
The negative side of a welding unit

3. What is a solenoid valve and what actuates it?
...
By there current carrying capacity
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

4. What would be an indication that the drive roll pressure is adjusted correctly?
Guns
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)
Welding process that joins metals by heating them with an electric arc

5. What output on the welding machine is used to rate the duty cycle?
Short- circuiting transfer - Globular transfer - Spray transfer
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle

6. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
...

7. What is the main purpose of 'slope'?
AWS and CSA
To limit the short circuiting current so that spatter is reduced
If you dont know this check your phone
Pressure vessels and the piping industry

8. 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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode

9. What does the term GMAW identify?
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

10. What is the maximum distance that hard wire can be successfully pushed?
Dry ice can form within the flow control openings and cause blockage of shielding gas
15 feet (4.5 meters)
Generally not as accurate
Wire feeds smoothly (yet will slip should a problem occur in the gun)

11. What is the key advantage of short circuiting transfer?
National Electrical Manufactures Association
Gives arc voltage values to the control system of the feeder
Minimum distortion due to low heat input
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. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Minutes of elapsed time continually run (out of 10 minutes)
Voltage is the force that overcomes resistance to allow amperage flow
20 to 200 times per second

13. 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
Voltage is the force that overcomes resistance to allow amperage flow
5.8 to 12.5 L/min
(DCEP) Direct Current Electrode Positive or Reverse polarity

14. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect

15. What does the abbreviation NEMA stand for?
Flux cored wires
1/4 inch to 1/2 inch
The Arc voltage
National Electrical Manufactures Association

16. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Guns
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube

17. How are GMAW guns rated?
By there current carrying capacity
Flux cored wires
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

18. What does the wire feeder control?
Penetration and burn - off rate of the electrode
National Electrical Manufactures Association
Speed of the feed motor and - starting / stopping electrode feed
20 to 200 times per second

19. List the three methods of metal transfer with GMAW
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
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
Puddle fluidity

20. List several industries that would use GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent leakage - Carbon Dioxide (CO2)

21. What 2 controls are found on a GMAW set- up?
3
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)
Minimum distortion due to low heat input

22. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
If you dont know this check your phone
Penetration and burn - off rate of the electrode

23. List the factors that determine the mode of metal transfer
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit
Flux cored wires

24. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
AWS and CSA
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

25. Why is a line heater required when using GMAW?
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant current (CC)

26. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
The Arc voltage
Duty cycle
Shielding the molten weld metal from atmospheric contamination

27. What is an advantage of pulsed arc transfer with GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
SMAW - GTAW

28. Give a brief description of the GMAW process
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Higher 26 to 35 arc volts
Welding process that joins metals by heating them with an electric arc

29. What is the recommended electrode stick- out for .035 solid wire?
Constant voltage (CV)
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Pressure - The rate of flow of a shielding gas

30. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
3
Welding process that joins metals by heating them with an electric arc
Gas metal arc welding

31. What does inductance control?
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination

32. What is the required arc voltage used for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
85%
By there current carrying capacity
12 to 22 arc volts

33. What are the 2 types of wire feeders available?
Penetration and burn - off rate of the electrode
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders

34. A pull type drive system is usually used on what type of material?
Insufficient current to melt the wire off cleanly
Aluminum wire
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow

35. Regulators control_____________ flowmeters SHOW____________.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas
The negative side of a welding unit
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced

37. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The Arc voltage
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced
Dry ice can form within the flow control openings and cause blockage of shielding gas

38. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
1/4 inch to 1/2 inch
Dry ice can form within the flow control openings and cause blockage of shielding gas
If you dont know this check your phone

39. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance
If you dont know this check your phone
1/4 inch to 1/2 inch

40. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant voltage (CV)
Voltage is the force that overcomes resistance to allow amperage flow
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate

41. What controls amperage when using GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Guns
Wire feed speed

42. What does a flowmeter do and what does it measure?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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 drawing of liquid CO2 (Carbon Dioxide)

43. List 3 wire drive systems and give a short description of each
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
National Electrical Manufactures Association

44. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant voltage (CV)
Aluminum wire
3
85%

45. List 3 forms compressed gases may be supplied for welding
Voltage is the force that overcomes resistance to allow amperage flow
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
15 feet (4.5 meters)
Insufficient current to melt the wire off cleanly

46. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Speed of the feed motor and - starting / stopping electrode feed
Penetration and burn - off rate of the electrode
3
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

47. What current and polarity is generally used with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association
If you dont know this check your phone
DCEP (Direct Current Electrode Positive) Reverse Polarity

48. 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
Minimum distortion due to low heat input
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)

49. Why is the term GMAW preferred over MIG or MAG?
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect
20 to 200 times per second

50. With straight polarity where is 2/3 of the arc energy?
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
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 negative side of a welding unit