Wire questions Flashcards
What is the preferred power source for GMAW?
Constant voltage Direct current electrode positive (DCEP)
What are the three modes of metal transfer?
Short circuit, globular, and spray
What can be welded with GMAW?
carbon and alloy steels, stainless steel, several non-ferrous metals (aluminum).
What’s main reason for shielding gas?
prevents atmospheric contamination
Advantages of MCAW?
Fast, high productivity, no slag, no spatter, no cleaning between passes.
Three types of power sources for wire feed?
motor driven generators and alternators, transformer rectifiers and inverters.
What type of wire feeder is used with a CV power source?
Constant speed wire feeder.
What does a flowmeter do?
Controls the rate of flow of a shielding gas. In litres per minute or cubic feet per hour
What is duty cycle?
Duty cycle is the amount of time, out of ten minutes, that a welder can run at maximum amperage.
What type of volt/amp curve does a CC machine have?
CC has a drooping type volt/amp curve SMAW (stick)
What type of volt/amp curve does a CV machine have?
CV has a relatively flat volt/amp curve. GMAW
What does wire feed speed control with a CV machine?
Wire speed controls amperage.
What is important to have when welding with shielding gases?
A ventilation system.
What produces poisonous chemical fumes when welding?
Chlorinated degreasers (brake clean)
Self shielded FCAW uses shielding gas produced from?
The shielding gas is produced from the internal flux
How are wire feed guns and other components rated?
Rated according to current carrying capacity
Which shielding gases are inert?
Argon and Helium
Why would 1-9% oxygen be added to argon shielding gas?
1-9% oxygen would improve the wetting action
What gas is required to have “true” spray trasfer?
a minimum of 85% argon is required for true spray transfer.
What should be followed for all power source maintenance?
Follow manufacturers reccomendations
Who can install a welding power supply?
Qualified personnel to local codes
What does slope do?
Slope limits the available amperage output
What two things can cause stubbing?
steep slope and excessive wire speed
What is electrode angle?
Position of the electrode in relation to the included joint angle. 90 degree joint = 45 degree electrode angle. Always have joint angle
