... Iron (heavier in weight, greater strength and resistance to wear); Heat-resisting Steel, Hypereutectic Al-Si Alloy ... Piston ProcessCasting, Forging, Melted Metal Squeezing.Piston StructurePiston Head, Piston Pin Bore, Piston Pin, Skirt, Ring Grooves, Ring Lands and Piston Rings.Piston ... Oxidization, Top Molybdenium Disulfide, Sn(tin)Plated on Skirt, Graphite on Skirt, Alfin, Double Alfin, None Alfin, ...