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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. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
5.8 to 12.5 L/min
V groove or U groove

2. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Penetration and burn - off rate of the electrode
To limit the short circuiting current so that spatter is reduced
3
Constant- speed wire feeders and Voltage- sennsing wire feeders

3. Why must CO2 cylinders be used in the vertical position?
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%

4. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
AWS and CSA

5. What is the disadvantage of the gauge preset type of regulator/flowmeter?
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Generally not as accurate
Speed of the feed motor and - starting / stopping electrode feed

6. What is the preferred drive roll design for solid wires?
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
...
These terms are quite restrictive and often technically incorrect

7. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Constant current (CC)
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW
Flux cored wires

8. What is another term for electrode holders for GMAW?
Puddle fluidity
The time rate of response for the current rise and fall
Guns
When the filler wire is in direct contract with the base metal

9. What is an advantage of pulsed arc transfer with GMAW?
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
These terms are quite restrictive and often technically incorrect

10. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
SMAW - GTAW
Flux cored wires
Wire feed speed

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
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect
Minimum distortion due to low heat input

12. What is the recommended electrode stick- out for .035 solid wire?
Gas metal arc welding
V groove or U groove
DCEP (Direct Current Electrode Positive) Reverse Polarity
1/4 inch to 1/2 inch

13. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Puddle fluidity
85%
Duty cycle

14. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas
The time rate of response for the current rise and fall

15. When is the metal transferred with short circuit transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed - Voltage control
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input

16. What does a flowmeter do and what does it measure?
12 to 22 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)

17. List the three methods of metal transfer with GMAW
3
Short- circuiting transfer - Globular transfer - Spray transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity
12 to 22 arc volts

18. 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
When the filler wire is in direct contract with the base metal
3
To prevent leakage - Carbon Dioxide (CO2)

19. A pull type drive system is usually used on what type of material?
Pressure vessels and the piping industry
Aluminum wire
Penetration and burn - off rate of the electrode
Generally not as accurate

20. What is the main purpose of 'slope'?
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced
Reducing the gas source pressure to a constant working pressure

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

22. How many times per second does short circuiting take place?
These terms are quite restrictive and often technically incorrect
Constant current (CC)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second

23. What is a typical flow rate of CO2 for short circuit transfer?
Constant voltage (CV)
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min
Spatter problems and poor weld appearance

24. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Wire feed speed
Welding process that joins metals by heating them with an electric arc
Voltage is the force that overcomes resistance to allow amperage flow

25. What output on the welding machine is used to rate the duty cycle?
3
Minutes of elapsed time continually run (out of 10 minutes)
By there current carrying capacity
Dry ice can form within the flow control openings and cause blockage of shielding gas

26. Why is a line heater required when using GMAW?
3
Reducing the gas source pressure to a constant working pressure
Wire feed speed
Dry ice can form within the flow control openings and cause blockage of shielding gas

27. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
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
...
Flux cored wires
12 to 22 arc volts

28. What controls amperage when using GMAW?
...
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder
Wire feed speed

29. With straight polarity where is 2/3 of the arc energy?
Minimum distortion due to low heat input
The negative side of a welding unit
Shielding the molten weld metal from atmospheric contamination
Aluminum wire

30. Give a brief description of the GMAW process
Minimum distortion due to low heat input
Welding process that joins metals by heating them with an electric arc
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
(DCEP) Direct Current Electrode Positive or Reverse polarity

31. List the factors that determine the mode of metal transfer
Aluminum wire
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second

32. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage
When the filler wire is in direct contract with the base metal
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

33. What processes are constant current (CC) power sources designed to be used with?
Speed of the feed motor and - starting / stopping electrode feed
Controls the rate of flow of a shielding gas to the gun nozzle
SMAW - GTAW
Minimum distortion due to low heat input

34. Draw a typical volt amp curve for a machine that is designed for GMAW
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Speed of the feed motor and - starting / stopping electrode feed

35. Why is globular transfer generally avoided with GMAW?
Duty cycle
Spatter problems and poor weld appearance
Generally not as accurate
Constant voltage (CV)

36. What does the wire feeder control?
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder

37. What does the term GMAW identify?
Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
When the filler wire is in direct contract with the base metal
Gas metal arc welding

38. List 3 wire drive systems and give a short description of each
Spatter problems and poor weld appearance
To prevent leakage - Carbon Dioxide (CO2)
Guns
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

39. 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
Higher 26 to 35 arc volts
Flux cored wires
Minimum distortion due to low heat input

40. List 3 forms compressed gases may be supplied for welding
Speed of the feed motor and - starting / stopping electrode feed
Higher 26 to 35 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
If you dont know this check your phone

41. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
...
Pressure vessels and the piping industry
12 to 22 arc volts
Higher 26 to 35 arc volts

42. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Shielding the molten weld metal from atmospheric contamination
3
85%
To limit the short circuiting current so that spatter is reduced

43. Regulators control_____________ flowmeters SHOW____________.
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)
The negative side of a welding unit
Pressure - The rate of flow of a shielding gas

44. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube

45. 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
85%
1/4 inch to 1/2 inch
Wire feed speed

46. What is the key advantage of short circuiting transfer?
By there current carrying capacity
Minimum distortion due to low heat input
Constant current (CC)
Gas metal arc welding

47. How are GMAW guns rated?
5.8 to 12.5 L/min
Cause flaking - which can clog the liner and contact tube
By there current carrying capacity
1/4 inch to 1/2 inch

48. What are the 2 types of wire feeders available?
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders

49. In the GMAW process what does amperage control?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode

50. What type of power source is commonly used with a voltage sensing wire feeder?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Aluminum wire
Constant current (CC)
Gas metal arc welding