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Test your basic knowledge |
Gas Metal Arc Welding
Start Test
Study First
Subject
:
engineering
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
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 output on the welding machine is used to rate the duty cycle?
Voltage is the force that overcomes resistance to allow amperage flow
National Electrical Manufactures Association
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
2. What effect does increasing and decreasing the inductance have on the weld?
Voltage is the force that overcomes resistance to allow amperage flow
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
1/4 inch to 1/2 inch
(DCEP) Direct Current Electrode Positive or Reverse polarity
3. What does voltage do in an electrical circuit?
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow
4. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Guns
When the filler wire is in direct contract with the base metal
Voltage is the force that overcomes resistance to allow amperage flow
5. 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
V groove or U groove
If you dont know this check your phone
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
6. What does inductance control?
5.8 to 12.5 L/min
If you dont know this check your phone
The time rate of response for the current rise and fall
Gives arc voltage values to the control system of the feeder
7. What controls amperage when using GMAW?
Flux cored wires
Generally not as accurate
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
8. What type of power source is commonly used with a voltage sensing wire feeder?
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc
Constant current (CC)
Speed of the feed motor and - starting / stopping electrode feed
9. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Constant current (CC)
Constant voltage (CV)
Generally not as accurate
10. How many times per second does short circuiting take place?
Flux cored wires
20 to 200 times per second
Higher 26 to 35 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity
11. What is the maximum distance that hard wire can be successfully pushed?
V groove or U groove
Welding process that joins metals by heating them with an electric arc
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12. In the GMAW process what does amperage control?
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
13. What would be an indication that the drive roll pressure is adjusted correctly?
85%
Wire feed speed - Voltage control
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)
14. List the three methods of metal transfer with GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
15. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
16. What does the term GMAW identify?
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
Higher 26 to 35 arc volts
17. List the factors that determine the mode of metal transfer
By there current carrying capacity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%
15 feet (4.5 meters)
18. What power sources are used with the GMAW Process?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Motor driven generators - Transformer rectifiers - and Inverter designs
Higher 26 to 35 arc volts
Voltage is the force that overcomes resistance to allow amperage flow
19. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
20. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
21. What is the purpose of the shielding gas used in GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry
Pressure - The rate of flow of a shielding gas
Shielding the molten weld metal from atmospheric contamination
22. In the GMAW process what does voltage control?
15 feet (4.5 meters)
Puddle fluidity
Insufficient current to melt the wire off cleanly
85%
23. What is the preferred drive roll design for solid wires?
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
V groove or U groove
Constant current (CC)
24. What does the wire feeder control?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed
25. What is the effect of too much slope?
3
Spatter problems and poor weld appearance
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
26. A pull type drive system is usually used on what type of material?
National Electrical Manufactures Association
Gives arc voltage values to the control system of the feeder
Short- circuiting transfer - Globular transfer - Spray transfer
Aluminum wire
27. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feed speed - Voltage control
Shielding the molten weld metal from atmospheric contamination
28. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Constant- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
29. List 3 forms compressed gases may be supplied for welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
30. What does a flowmeter do and what does it measure?
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
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage
Flux cored wires
31. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
32. Give a description of 'pinch effect'
Dry ice can form within the flow control openings and cause blockage of shielding gas
To prevent leakage - Carbon Dioxide (CO2)
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
33. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
15 feet (4.5 meters)
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas
34. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Guns
12 to 22 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer
35. What is the key advantage of short circuiting transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
3
Minimum distortion due to low heat input
36. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Cause flaking - which can clog the liner and contact tube
...
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
37. What type of power source is used with a constant speed wire feeder?
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit
Constant voltage (CV)
15 feet (4.5 meters)
38. 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
20 to 200 times per second
Penetration and burn - off rate of the electrode
39. Draw a typical volt amp curve for a machine that is designed for GMAW
SMAW - GTAW
If you dont know this check your phone
The Arc voltage
Pressure - The rate of flow of a shielding gas
40. What is a typical flow rate of CO2 for short circuit 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
5.8 to 12.5 L/min
Aluminum wire
Reducing the gas source pressure to a constant working pressure
41. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires
42. When is the metal transferred with short circuit transfer?
V groove or U groove
Gas metal arc welding
When the filler wire is in direct contract with the base metal
If you dont know this check your phone
43. What is the main purpose of 'slope'?
Pressure - The rate of flow of a shielding gas
Gives arc voltage values to the control system of the feeder
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
44. List several industries that would use GMAW
V groove or U groove
Pressure vessels and the piping industry
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
45. 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
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove
Penetration and burn - off rate of the electrode
46. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed
3
Constant current (CC)
47. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
48. What happens when the electrode extension is increased?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The resistace to electrical current flow increases with it. Causing the electrode to heat
National Electrical Manufactures Association
Speed of the feed motor and - starting / stopping electrode feed
49. Why is a fiber washer required and what cylinder gas requires it?
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
15 feet (4.5 meters)
Wire feed speed
50. How are GMAW guns rated?
To prevent drawing of liquid CO2 (Carbon Dioxide)
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone