A special application is hard chrome plating of marine diesel engine's (SULZER, MAN B&W, PIELSTICK, MITSUBISHI, etc.), piston crown ring grooves. "METALCHROM" has designed and developed a proprietary system/process of rotational plating of piston crowns that is been granted as a patent (No 1000555/14-2-92, Int. Cl5. C25D 7/04), at the Industrial Property Organization (OBI).