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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. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Pressure vessels and the piping industry
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube
Wire feed speed
2. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube
Generally not as accurate
Minutes of elapsed time continually run (out of 10 minutes)
3. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
AWS and CSA
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Dry ice can form within the flow control openings and cause blockage of shielding gas
4. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
1/4 inch to 1/2 inch
3
DCEP (Direct Current Electrode Positive) Reverse Polarity
5. What would be an indication that the drive roll pressure is adjusted correctly?
SMAW - GTAW
Pressure vessels and the piping industry
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts
6. Why is a line heater required when using GMAW?
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Dry ice can form within the flow control openings and cause blockage of shielding gas
7. In the GMAW process what does voltage control?
Puddle fluidity
...
15 feet (4.5 meters)
Generally not as accurate
8. What does a flowmeter do and what does it measure?
If you dont know this check your phone
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
When the filler wire is in direct contract with the base metal
9. Draw a typical volt amp curve for a machine that is designed for GMAW
The negative side of a welding unit
Guns
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
10. Give a description of 'pinch effect'
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
If you dont know this check your phone
Guns
11. Regulators control_____________ flowmeters SHOW____________.
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant voltage (CV)
12. What current and polarity is generally used with GMAW?
Wire feed speed
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity
13. Why must CO2 cylinders be used in the vertical position?
20 to 200 times per second
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
To prevent drawing of liquid CO2 (Carbon Dioxide)
85%
14. What output on the welding machine is used to rate the duty cycle?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
15. What is the preferred drive roll design for solid wires?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
16. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube
Higher 26 to 35 arc volts
3
17. List several industries that would use GMAW
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts
Pressure - The rate of flow of a shielding gas
Pressure vessels and the piping industry
18. What type of power source is used with a constant speed wire feeder?
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
19. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
Puddle fluidity
Welding process that joins metals by heating them with an electric arc
20. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW
Shielding the molten weld metal from atmospheric contamination
21. Why is globular transfer generally avoided 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
Spatter problems and poor weld appearance
DCEP (Direct Current Electrode Positive) Reverse Polarity
When the filler wire is in direct contract with the base metal
22. What does the abbreviation NEMA stand for?
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
Wire feed speed
3
National Electrical Manufactures Association
23. What does voltage do in an electrical circuit?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Voltage is the force that overcomes resistance to allow amperage flow
SMAW - GTAW
Aluminum wire
24. What is the recommended electrode stick- out for .035 solid wire?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
Cause flaking - which can clog the liner and contact tube
1/4 inch to 1/2 inch
25. What is the required arc voltage used for short circuit transfer?
5.8 to 12.5 L/min
If you dont know this check your phone
12 to 22 arc volts
The Arc voltage
26. List 3 forms compressed gases may be supplied for welding
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
12 to 22 arc volts
27. When is the metal transferred with short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance
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
28. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
29. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
DCEP (Direct Current Electrode Positive) Reverse Polarity
Generally not as accurate
Duty cycle
30. What is an advantage of pulsed arc transfer with GMAW?
By there current carrying capacity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%
Guns
31. What is a solenoid valve and what actuates it?
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires
DCEP (Direct Current Electrode Positive) Reverse Polarity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
32. In the GMAW process what does amperage 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
Penetration and burn - off rate of the electrode
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate
33. What does inductance control?
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Duty cycle
34. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
3
1/4 inch to 1/2 inch
(DCEP) Direct Current Electrode Positive or Reverse polarity
35. 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
Guns
By there current carrying capacity
These terms are quite restrictive and often technically incorrect
36. How are GMAW guns rated?
The negative side of a welding unit
By there current carrying capacity
When the filler wire is in direct contract with the base metal
AWS and CSA
37. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
5.8 to 12.5 L/min
Puddle fluidity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
38. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
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
85%
Pressure vessels and the piping industry
39. Give a brief description of the GMAW process
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association
Welding process that joins metals by heating them with an electric arc
SMAW - GTAW
40. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
15 feet (4.5 meters)
85%
AWS and CSA
Controls the rate of flow of a shielding gas to the gun nozzle
41. What does the wire feeder control?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed
Constant current (CC)
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
42. What controls the wire speed on a voltage sensing wire feeder?
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
The Arc voltage
43. What 2 controls are found on a GMAW set- up?
National Electrical Manufactures Association
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
Wire feed speed - Voltage control
44. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
...
Dry ice can form within the flow control openings and cause blockage of shielding gas
45. Why is a fiber washer required and what cylinder gas requires it?
Gives arc voltage values to the control system of the feeder
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)
These terms are quite restrictive and often technically incorrect
46. List the basic equipment requirements for the GMAW process
85%
Speed of the feed motor and - starting / stopping electrode feed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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
47. What controls amperage when using 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
Wire feed speed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
48. What power sources are used with the GMAW Process?
Reducing the gas source pressure to a constant working pressure
Constant voltage (CV)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Motor driven generators - Transformer rectifiers - and Inverter designs
49. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
50. What happens when the electrode extension is increased?
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
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity