EXOCARB® WXS® Ultra Premium Performance Carbide End Mills with OSG’s Proprietary WXS® Coating List 4540: Regular Length, Multiple Flute Standard Milling Hardness Up to 40 HRC 40 to 45 HRC 45 to 55 HRC 55 to 60 HRC 60 to 65 HRC 65 to 70 HRC WorkMaterial Mild SteelsCarbon SteelsCast IronTool SteelsHardened SteelsPre-hardenedSteels Hardened Steels Depthof Cut aa arD≤1.51.5D0.02D1.5