P4 Flashcards
What’s produced when welding power source is but NO arc exists
Open circuit voltage
The heat an arc creates ranges between
5500-6600
The mixtures of melted electrodes and melted base metal created by the welding current flowing through the electrode and across the arc is called?
The weld deposit
In shielded metal arc welding, metals are fused by the heat from an electric arc that is maintained between the surface of the workpiece and a ?
Coated electrode
In SMAW, what does electric coating do?
Protects the molten from the atmosphere
The “shielding” in the SMAW process is provided by
The electrode coating
What is the force called that causes current to flow in an electrical circuit
Voltage
The electrical pressure or voltage in a welding circuit after the arc has been struck is called?
Arc voltage
Electrical pressure is measured in?
Volts (V)
Electrical current flow is measured in
Amperes (A)
The electrical circuit in the SMAW process is closed at the point when
The arc is struck
Undercut is usually caused by improper electrode manipulation. Other causes are
To much current, To much Arc , To fast of travel
What is the purpose of “Fast Fill”
Used for production work, adds lots of filler metal at fast rate
What’s the purpose of “Fast Freeze”
Deposits weld bead that can solidify or freeze quickly, good for welding overhead or virtacle
What is the purpose of “Fill freeze” (fast follow)
Fill freeze allows for faster speed with consistent bead, main use is to use little fill on light gauge metal
What is “Low hydrogen” Basic
Hydrogen can be harmful to metal properties
And become trapped in deposits causing it to crack, (hours after finished)
Internal stress causes under bead cracking
To protect it, it is used with no organic substances containing hydrogen
Electrode dimensions (diameter) range from mm/”
1.6 mm 1/16 - 8mm 5/16
Electrode lengths range from and most commen length is
225mm 9” to 1000mm 36”
Most common 350mm 14”
BASIC FUNCTION of welding electrode in an arc welding circuit is to
Carry the current that generates the arc
Must also melt and fuse metal to create proper weld
Bare-wire electrodes were designed to
Eliminate need for separate filler material
Flux coating has 6 functions it performs
- forms gas shield to keep gas and oxy from pool
- controls electric arc stream
- adds alloying elements + filler to weld metal
- cleans weld pool by floating impurities and oxygen
- forms cover that shapes cooling metal from oxidization
- forms cover of slag to reduce cooling rate
Cellulose does what
Forms cup type shield at electrode tip. It gives direction to shielding gases and arc stream forms gas envelope of carbon dioxide and water vapour
What’s Rutile
“Titanium dioxide” makes the arc smooth and stable, and forms a hard black slag to make for a smooth finish
China clay, silica, mica
Used for electrode coating to provide volume, controls viscosity and surface tension of slag and freeze rate of slag
Potassium
Used as arc stabilizer and ionizer to help ease and stabilize current flow
Ferro-manganese
Removes oxygen from arc ferro-manganese then forms with oxygen to form an oxide to make slag
Sodium silicate (water glass)
Heavy liquid sticky to bind materials and coat core wire
