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Test your basic knowledge |
Gas Metal Arc Welding
Subject
:
engineering
Instructions:
Answer
50
questions in
20 minutes
.
2 minutes extra for reading the instructions.
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. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Constant voltage (CV)
Welding process that joins metals by heating them with an electric arc
Pressure - The rate of flow of a shielding gas
2. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Insufficient current to melt the wire off cleanly
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3. What would be an indication that the drive roll pressure is adjusted correctly?
...
The time rate of response for the current rise and fall
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
4. What does voltage do in an electrical circuit?
The Arc voltage
Reducing the gas source pressure to a constant working pressure
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
5. What processes are constant current (CC) power sources designed to be used with?
Spatter problems and poor weld appearance
3
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW
6. What type of power source is commonly used with a voltage sensing wire feeder?
By there current carrying capacity
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)
7. What does the term GMAW identify?
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding
These terms are quite restrictive and often technically incorrect
Wire feeds smoothly (yet will slip should a problem occur in the gun)
8. List the basic equipment requirements for the GMAW process
...
Voltage is the force that overcomes resistance to allow amperage flow
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
9. Why is the term GMAW preferred over MIG or MAG?
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect
If you dont know this check your phone
Guns
10. What is the effect of too much slope?
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
Insufficient current to melt the wire off cleanly
5.8 to 12.5 L/min
11. Regulators control_____________ flowmeters SHOW____________.
Wire feed speed
Flux cored wires
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
12. What is a solenoid valve and what actuates it?
Minimum distortion due to low heat input
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
13. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder
14. What controls amperage when using GMAW?
Pressure vessels and the piping industry
Spatter problems and poor weld appearance
Cause flaking - which can clog the liner and contact tube
Wire feed speed
15. What 2 organizations designate specifications for GMAW wires?
Reducing the gas source pressure to a constant working pressure
AWS and CSA
Gives arc voltage values to the control system of the feeder
By there current carrying capacity
16. What type of power source is used with a constant speed wire feeder?
Pressure vessels and the piping industry
SMAW - GTAW
Constant voltage (CV)
Constant current (CC)
17. What is the recommended electrode stick- out for .035 solid wire?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
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. List the factors that determine the mode of metal transfer
12 to 22 arc volts
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
19. Why is globular transfer generally avoided with GMAW?
Penetration and burn - off rate of the electrode
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)
Spatter problems and poor weld appearance
20. Why is a line heater required when using GMAW?
The time rate of response for the current rise and fall
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Speed of the feed motor and - starting / stopping electrode feed
21. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
If you dont know this check your phone
Short- circuiting transfer - Globular transfer - Spray transfer
3
22. List several industries that would use GMAW
The negative side of a welding unit
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry
12 to 22 arc volts
23. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
Shielding the molten weld metal from atmospheric contamination
Duty cycle
24. When is the metal transferred with short circuit transfer?
Minimum distortion due to low heat input
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
25. What are the 2 types of wire feeders available?
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding process that joins metals by heating them with an electric arc
Higher 26 to 35 arc volts
26. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Generally not as accurate
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
27. What is another term for electrode holders for GMAW?
Guns
If you dont know this check your phone
Higher 26 to 35 arc volts
Cause flaking - which can clog the liner and contact tube
28. Give a brief description of the GMAW process
By there current carrying capacity
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
Welding process that joins metals by heating them with an electric arc
29. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube
30. What is a typical flow rate of CO2 for short circuit transfer?
3
Controls the rate of flow of a shielding gas to the gun nozzle
5.8 to 12.5 L/min
Higher 26 to 35 arc volts
31. What is the preferred drive roll design for solid wires?
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
85%
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
32. What current and polarity is generally used with GMAW?
National Electrical Manufactures Association
...
Guns
DCEP (Direct Current Electrode Positive) Reverse Polarity
33. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Higher 26 to 35 arc volts
12 to 22 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
34. What is the maximum distance that hard wire can be successfully pushed?
The resistace to electrical current flow increases with it. Causing the electrode to heat
15 feet (4.5 meters)
If you dont know this check your phone
...
35. In the GMAW process what does voltage control?
Puddle fluidity
The time rate of response for the current rise and fall
Pressure vessels and the piping industry
The Arc voltage
36. Draw a typical volt amp curve for a machine that is designed for GMAW
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
85%
If you dont know this check your phone
37. Give a description of 'pinch effect'
Duty cycle
85%
Controls the rate of flow of a shielding gas to the gun nozzle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
38. What 2 controls are found on a GMAW set- up?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control
By there current carrying capacity
39. What power sources are used with the GMAW Process?
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal
Motor driven generators - Transformer rectifiers - and Inverter designs
40. What does the wire feeder control?
Wire feed speed
Speed of the feed motor and - starting / stopping electrode feed
Gas metal arc welding
3
41. What happens when the electrode extension is increased?
Voltage is the force that overcomes resistance to allow amperage flow
Gives arc voltage values to the control system of the feeder
The resistace to electrical current flow increases with it. Causing the electrode to heat
Speed of the feed motor and - starting / stopping electrode feed
42. What does a flowmeter do and what does it measure?
85%
Puddle fluidity
The negative side of a welding unit
Controls the rate of flow of a shielding gas to the gun nozzle
43. List the three methods of metal transfer with GMAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
...
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle
44. What does inductance control?
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
National Electrical Manufactures Association
45. What is an advantage of pulsed arc transfer with GMAW?
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
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min
46. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
15 feet (4.5 meters)
To prevent drawing of liquid CO2 (Carbon Dioxide)
47. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
Guns
48. In the GMAW process what does amperage control?
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode
If you dont know this check your phone
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
49. How are GMAW guns rated?
By there current carrying capacity
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
Shielding the molten weld metal from atmospheric contamination
50. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Gas metal arc welding
85%
1/4 inch to 1/2 inch
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld