Ball Valve Balls with Hard Chrome, also know as industrial chrome or engineered chrome, is used to reduce friction, add wear resistance, or increase corrosion resistance. it is very hard, measuring between 66 to 70 HRC. Hard chrome tends to be thicker than the decorative treatement, typically ranging from 0.075 to 0.25 milimetre (0.0030 to 0.0098 in), but can range from 0.005 to 0.01 mil (0.00013 to 0.00025 mm). Surface defects and roughness are amplified, because hard chrome does not have a leveling effect. Hard chromium plating is subject to different types of quality requirement depending on the application, for instance, the plating on hydraulic piston rods are tested for corrosion resistance with a salt spray test.