Complex sentence: Typical workpiece materials include aluminum, brass, bronze, and mild steel because of their outstanding shearability ratings, however, stainless steel is not used as much due to its tendencies to work-harden.
Split into simpler sentences: Typical workpiece materials include aluminum, brass, bronze, and mild steel because of their outstanding shearability ratings. Stainless steel is not sheared as often due to its tendencies to work-harden.