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Cermet Inserts

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Florida Machinist Group Moderator
H-M Supporter-Premium Member
Feb 7, 2014
I am low on inserts, so I was searching ebay to see if anything worthwhile was available. I ran into this "TCMT110204 NX2525 TCMT21.51". The description is that they are ceramic-metal inserts. I looked at other vendors and also found them listed as Cermet. I then did a general forum search for cermet and got nothing. How does this compare to carbide inserts.


Active User
H-M Supporter-Premium Member
Jun 12, 2014
Have not used Cermet inserts, but thy would appear that they are more applicable to finish work. I would stay with standard carbide inserts, they would be less prone to breakage and can handle a wide range of cutting conditions.

Cermet from Sandvik site.
Definition and properties: A cermet is a cemented carbide with titanium based hard particles. The name cermet combines the words ceramic and metal. Originally, cermets were composites of TiC and nickel. Modern cermets are nickel-free and have a designed structure of titanium carbonitride Ti(C,N) core particles, a second hard phase of (Ti,Nb,W)(C,N) and a W-rich cobalt binder. Ti(C,N) adds wear resistance to the grade, the second hard phase increases the plastic deformation resistance, and the amount of cobalt controls the toughness. In comparison to cemented carbide, cermet has improved wear resistance and reduced smearing tendencies. On the other hand, it also has lower compressive strength and inferior thermal shock resistance. Cermets can also be PVD coated for improved wear resistance.

Cermet grades are used in smearing applications where built-up edge is a problem. Its self-sharpening wear pattern keeps cutting forces low even after long periods in cut. In finishing operations, this enables a long tool life and close tolerances, and results in shiny surfaces. Typical applications are finishing in stainless steels, nodular cast irons, low carbon steels and ferritic steels. Cermets can also be applied for trouble shooting in all ferrous materials.

Use low feed and depth of cut.
Change the insert edge when flank wear reaches 0.3 mm.
Avoid thermal cracks and fractures by machining without coolant.


HM Shop Superintendent
Staff member
H-M Supporter - Sustaining Member
Aug 8, 2011
Even Though they are a finishing insert, For most of us, they are fine for general work we do. Most of us are not doing production work where this insert would not be good for roughing or heaving machining. I have a few types in Cermet grades I've picked up just because the price was right. I couldn't say I've used any of them yet off hand.
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