No!
I used to work as a mechanic, that is how I payed for my first year of college. Discs, Drums and their pads have different amounts of aspestos and other materials that do not let the steel temper, older cars are an exception, some discs wear away faster than others, depends also on the pads. (I wont get too into it, but there is a difference. When you race these things matter.)
They have no place in knife making.
However, we all know spring steels make neato knives... so there you go.