Does the quality of the item affect the quality of the salvaged components?

Nicer quality items have more components, so you can potentially get more parts out of them. The quality of the component is pre-defined based on what the item is.

For example, salvaging an Iron Longsword will never give you any other blade than an Iron Blade, while a Steel Longsword will never give you any other blade than a Steel Blade

It's random as to what and how many components you get, however higher blacksmithing levels will increase your chance at salvaging the item's components, so you'll likely get more pieces from it.

You can also save / load your game if there's a particular component of an item that you want, such as a life steal component, or mana steal.