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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. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)
To limit the short circuiting current so that spatter is reduced

2. When is the metal transferred with short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
When the filler wire is in direct contract with the base metal
Duty cycle
Wire feed speed

3. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
To prevent drawing of liquid CO2 (Carbon Dioxide)
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

4. What type of power source is used with a constant speed wire feeder?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control
Wire feed speed
Constant voltage (CV)

5. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gas metal arc welding
85%
These terms are quite restrictive and often technically incorrect

6. What is the maximum distance that hard wire can be successfully pushed?
The Arc voltage
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

7. List the factors that determine the mode of metal transfer
15 feet (4.5 meters)
Gas metal arc welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of 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

8. What processes are constant current (CC) power sources designed to be used with?
Higher 26 to 35 arc volts
SMAW - GTAW
Aluminum wire
DCEP (Direct Current Electrode Positive) Reverse Polarity

9. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
...

10. What is the main purpose of 'slope'?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)

11. What are the 2 types of wire feeders available?
Gives arc voltage values to the control system of the feeder
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
National Electrical Manufactures Association

12. What controls the wire speed on a voltage sensing wire feeder?
Spatter problems and poor weld appearance
The Arc voltage
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle

13. What wire are knurled drive rolls most commonly used on?
Controls the rate of flow of a shielding gas to the gun nozzle
20 to 200 times per second
...
Flux cored wires

14. List the three methods of metal transfer with GMAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer
Spatter problems and poor weld appearance
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

15. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Guns
Flux cored wires
Gives arc voltage values to the control system of the feeder

16. What is the preferred drive roll design for solid wires?
1/4 inch to 1/2 inch
V groove or U groove
Constant voltage (CV)
To limit the short circuiting current so that spatter is reduced

17. What controls amperage when using GMAW?
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
Wire feed speed
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

18. Why is globular transfer generally avoided with GMAW?
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
AWS and CSA
Spatter problems and poor weld appearance

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
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
Puddle fluidity
85%

20. What is an advantage of pulsed arc transfer with GMAW?
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
Welding process that joins metals by heating them with an electric arc
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure - The rate of flow of a shielding gas

21. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow
Minimum distortion due to low heat input

22. What is another term for electrode holders for GMAW?
Wire feed speed - Voltage control
85%
Guns
AWS and CSA

23. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
15 feet (4.5 meters)
When the filler wire is in direct contract with the base metal
3
Motor driven generators - Transformer rectifiers - and Inverter designs

24. How many times per second does short circuiting take place?
To limit the short circuiting current so that spatter is reduced
20 to 200 times per second
12 to 22 arc volts
Aluminum wire

25. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)
Insufficient current to melt the wire off cleanly
Cause flaking - which can clog the liner and contact tube

26. In the GMAW process what does voltage control?
Puddle fluidity
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas

27. Draw a typical volt amp curve for a machine that is designed for GMAW
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
Duty cycle
If you dont know this check your phone

28. A pull type drive system is usually used on what type of material?
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
National Electrical Manufactures Association
Aluminum wire

29. What effect does increasing and decreasing the inductance have on the weld?
Gas metal arc welding
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
...
Duty cycle

30. Why is the term GMAW preferred over MIG or MAG?
Insufficient current to melt the wire off cleanly
SMAW - GTAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
These terms are quite restrictive and often technically incorrect

31. What is a typical flow rate of CO2 for short circuit transfer?
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
Minimum distortion due to low heat input
If you dont know this check your phone

32. In the GMAW process what does amperage control?
Insufficient current to melt the wire off cleanly
Cause flaking - which can clog the liner and contact tube
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

33. Why must CO2 cylinders be used in the vertical position?
To limit the short circuiting current so that spatter is reduced
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)
To prevent drawing of liquid CO2 (Carbon Dioxide)

34. What would be an indication that the drive roll pressure is adjusted correctly?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Aluminum wire
Voltage is the force that overcomes resistance to allow amperage flow

35. What does the abbreviation NEMA stand for?
Welding process that joins metals by heating them with an electric arc
20 to 200 times per second
National Electrical Manufactures Association
(DCEP) Direct Current Electrode Positive or Reverse polarity

36. What does the wire feeder control?
Gives arc voltage values to the control system of the feeder
Spatter problems and poor weld appearance
Puddle fluidity
Speed of the feed motor and - starting / stopping electrode feed

37. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Duty cycle
By there current carrying capacity
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA

38. What does inductance control?
Duty cycle
The time rate of response for the current rise and fall
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Speed of the feed motor and - starting / stopping electrode feed

39. Regulators control_____________ flowmeters SHOW____________.
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas
...
Wire feeds smoothly (yet will slip should a problem occur in the gun)

40. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Pressure vessels and the piping industry
Spatter problems and poor weld appearance
AWS and CSA

41. Why is a fiber washer required and what cylinder gas requires it?
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
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)

42. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Gives arc voltage values to the control system of the feeder
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle

43. What output on the welding machine is used to rate the duty cycle?
85%
Minimum distortion due to low heat input
When the filler wire is in direct contract with the base metal
Minutes of elapsed time continually run (out of 10 minutes)

44. What does a flowmeter do and what does it measure?
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent drawing of liquid CO2 (Carbon Dioxide)

45. What is the recommended electrode stick- out for .035 solid wire?
To prevent leakage - Carbon Dioxide (CO2)
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
If you dont know this check your phone
1/4 inch to 1/2 inch

46. How are GMAW guns rated?
By there current carrying capacity
Generally not as accurate
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed

47. What is the key advantage of short circuiting transfer?
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed - Voltage control
Minimum distortion due to low heat input
Gas metal arc welding

48. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Voltage is the force that overcomes resistance to allow amperage flow
5.8 to 12.5 L/min
15 feet (4.5 meters)

49. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)
AWS and CSA

50. 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
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
20 to 200 times per second