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Which carbide grade is appropriate for the material I am milling?

Certain carbide grades are better suited for milling certain materials.  The cutting tool manufacturer can help take the guess work out of determining which carbide grade is best for the material you are machining.  All of the standard carbide tipped milling cutters we offer (Side Milling Cutters, Slitting Saws, Keyseat Cutters, Counterbores, T-Slot cutters, Dovetail Cutters, Angle Cutters, End Mills, etc.) have material specific grades of carbide in them.  We tell you in our catalog and on our web site which material each type of cutter is designed to cut.

We primarily use two grades of carbide; C-2(m) and C-5.  C-2(m) is a general purpose grade of carbide that provides good wear resistance and is appropriate for most materials especially non-ferrous materials.  C-5 carbide is typically

used for cutters that will be machining steel as it has a greater resistance to wear and is harder and more brittle than C-2(m).  As a result C-5 carbide should only be used in steel and is not appropriate for machining other materials as it has a tendency to crack when not used in steel due to it being more brittle.  C-2(m) can be used in steel but the tool will wear quicker than the same tool using C-5 to machine steel.

C-2(m) is not appropriate for heat treated materials with a hardness greater than 39HRc (363 Brinell) even if it is a non-ferrous material.  For this type of application C-5 may be more appropriate.  Call us for a recommendation (941-751-9677).

If multiple materials are being machined with the same tool C-2(m) should be used even if steel is one of the materials (common in “sandwich” applications where you have multiple materials being machined in the same cut).  During the transition from one material to the next the hardness among other things changes.  Such a change can result in cracked carbide due to the brittleness of C-5.  To be safe stick with a cutter that uses C-2(m).

When milling most Stainless Steels and other types of high temperature alloys such as Titanium or Inconel C-2(m) is the most appropriate NOT C-5.  Just because Stainless Steel has the word “Steel” in it does not mean C-5 should be used.  The 400 series Stainless Steel is the exception to this rule (see chart below).

Below is a material chart showing which grade of carbide is appropriate for milling which materials.  This chart resembles our speeds and feeds charts.  The speeds and feeds we recommend are based on cutters with the appropriate carbide grade for the material being machined.

If you have questions on any of this please call us.  We are here to help and are happy to recommend which tool is most appropriate for the material you are machining.  Or, leave us a comment here on our blog or fill out the form on Super Tool’s Contact Us Page.

Bryan Enander
Super Tool, Inc.