Pulse welding - ANSWER by forming one droplet of molten metal at the end of the elec-
trode Then, just the right amount of current is added to push that one droplet across the arc
and into the puddle. The transfer of these droplets occurs through the arc, one droplet at a
time
4 Components of a Weld - ANSWER Metal, Heat Source, Filler Metal, Shield from Air
4 ARC Welding Processes - ANSWER stick, mig, tig, plasma cutting
ARC Welding - ANSWER type of welding where electricity jumps an air gap
Electricity - ANSWER electrons moving from one atom to another
Electron - ANSWER negatively charged portion of an atom, orbits around the nucleus
Conductor - ANSWER anything that allows electricity to flow easily through it, the further
away the electrons the better conductor
Insulator - ANSWER more difficult for electricity to flow through
Semi Conductor - ANSWER middle ground between insulator and conductor
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,Amperage - ANSWER how many electrons are moving
Voltage - ANSWER cause of electron movement, adjusting heat
Ohms - ANSWER resistance involved, adjusting the gap
Welding Hazards - ANSWER Personal Protection, Fumes, ARC radiation, electrical shock,
fire, burns, explosive gases
Galvanized Metal - ANSWER coated in zinc, dangerous to weld
Electrode - ANSWER a metal rod having approximately the same composition as the
metal to be welded
AC - ANSWER Alternating current, back and forth, most common
DC - ANSWER direct current, can go either straight or reverse
Purposes of Flux Coating - ANSWER cleansing and deoxidizing agent, release an inert gas
for protection from atmospheric oxides and nitrides, form slag over deposited metal to pro-
tect weld, easier starting, stabilizing the arc, reduced splatter, better penetration
First 2 digits of Electrode - ANSWER signify strength in thousands of pounds per square
inch
3rd digit of the Electrode - ANSWER signifies welding position; 1: any position; 2: horizon-
tal and flat only; 3: flat position
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,4th digit of the Electrode - ANSWER signifies special characteristics of the electrode
(welding quality, type of arc, amount of penetration)
ARC Welding Energy Source - ANSWER Heat generated by electric arc
Advantages of ARC Welding - ANSWER Low start up cost, profitability, outdoor use, all po-
sition welding, variety of materials, mechanical properties
Limitations of ARC Welding - ANSWER low efficiency (65%), operating factor, splatter, op-
erator skill, restarts, amperage limit, slag
Ideal Amperage for ARC Welding - ANSWER 80-90 amps
Gas Welding Set Up Procedure - ANSWER 1. make sure main valves are off and regulator
pressure adjusting screws are backed out with no pressure readings on gauge
2. ensure torch valves are off
3. stand to side and slowly turn on oxygen cylinder valve. once pressure reads on gauge
open valve all the way and backseat it.
4. stand to side and slowly turn on acetylene (1/2-3/4 turn) or slightly more, get a good
reading
5. set pressure on each regulator (oxy 7-10) (acetylene 7-10)
6. purge each hose individually by opening valves for a few seconds
7. light torch by opening acetylene valve (1/8-1/4 turn) and using torch strike
8. open acetylene torch valve until smoke goes away and flame isn't jumping
9. open oxygen torch valve until inner cone is defined
Gas Welding Shut Down - ANSWER 1. shut off acetylene and hen oxygen valves
2. open up acetylene and oxygen so no pressure read (left)
3. bleed acetylene and oxygen torch lines
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, 4. tighten gauges so they are shut (right)
Gas Welding Eye Protection - ANSWER requires safety glasses and welding goggles with a
number 4-6 lense
Base Metal - ANSWER metal to be welded
Fusion Welding - ANSWER process that joins metals by heating them to a melting point
and allowing them to fuse or flow together; melting, no filler
Penetration - ANSWER distance from the original surface of the base metal to that depth
at which fusion stops
Brazing - ANSWER joins two pieces of metal; similar to fusion but base metal is not
welded; no melting metal, bronze filler
TIG Welding - ANSWER Tungsten inert gas, higher melting point electrode, shielding gas is
argon or helium
Metals used in TIG Welding - ANSWER magnesium, aluminum, steel, stainless steel,
brass, alloys, silver, cast iron, copper
Advantages of TIG Welding - ANSWER easier, good on non-ferris metals (aluminum/stain-
less)
TIG Procedural Considerations - ANSWER Stick out (1/8 to 1/4 in), Arc Length (diameter
of electrode), Angle (15)
3 Types of Welding - ANSWER ARC, Gas, Resistance
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