Posted by Gordon England (62.252.0.12) on 12:04:03 17/12/04
In Reply to:hardness matching posted by Greg
Hi Greg
In an ideal world, the harder surface should wear less and two surfaces of equal hardness should wear the same.
In the real world we first need to understand the term hardness. Hardness is not an intrinsic material property dictated by precise definitions in terms of fundamental units of mass, length and time. A hardness property value is the result of a defined measurement procedure. So the way we measure and interpret hardness is important. Consider this example of a hardened steel at 60 HRc rubbing against a tungsten carbide/nickel alloy coated material at 50 HRc. In this case the so call softer material wears much less than the harder. Looking at the materials in a microscopic view the tungsten carbide/nickel alloy is a composite of extremely hard particles in a relatively soft matrix.
Just starting to scratch the surface of this very complex subject (tribology)!
Hardness is only one factor among many that need to be considered when assessing wear between surfaces.
Regards Gordon
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