Carbide Micrograin Carbide End Mills Standard 4 Flute and Multiple Flute Carbide: (continued) Slotting (Fractional) Hardness – – Up to 20 HRC 20 to 30 HRC 30 to 40 HRC 40 to 50 HRC WorkMaterial Aluminum Cast Iron Mild Carbon SteelsMild SteelsPre-hardenedSteelsDie & Alloy SteelsPre-hardenedSteelsDie & Alloy SteelsHardened Steels CuttingSpeed 330 SFM 100-150 SFM 100-130 SFM 65-100 SFM 65-82 SFM 43 SFM aa Depth D<1/32 0.2D of Cut 1/32