help with 3 questions on manual metal arc welding

by allan
(scotland)

in manual metal arc welding describe how the filler metal is delivered to the weld pool.how atmospheric contamination is prevented and how the heat source is generated.

--------------------------------------------------

filler metal is delivered to the weld pool in the form of a fine spray of droplets or in larger globular drops of molten metal depending on the type of rod and flux composition.

atmospheric contamination is prevented by the gas envelope created by the flux burning and also the molten flux while it is still molten in the puddle..it contains elements that scavenge impurities and float them to the surface.

the heat is created by the arc which is able to transfer extreme heat in that gas envelope created by the exclusion of atmosphere.