What is a piston head made out of and what grade is it?

A piston head is typically made from aluminum alloys or cast iron, with aluminum being more common due to its lightweight and good thermal conductivity. The specific grade can vary depending on the application, but common grades for aluminum used in piston heads include 2618 and 4032, which offer high strength and good wear resistance. For cast iron pistons, grades like ASTM A536 are often used for their durability.