Never feel stupid for asking. Every single one of us has many many subjects of which we know little or absolutely nothing.
If, what the smartest, oldest, and most studied of all of us knows about materials, and welding, and corrosion etc., were represented by a thimble full of water, what is left over to know would fill every ocean on the planet, and then some.
People have spent their entire lives studying and contributing to the most narrow aspects of our industry (for example the kinetics of fluxes in the weld puddle). It isn't possible to grasp it all.
Thats what makes it worthwhile.