ISO Failure mode classification for gears (ISO 10825)

Plastic deformation

A considerable amount of material has been displaced from the
top of the lobe surface towards the edges, where a burr is formed.

The generally accepted hardness on a finished cast cam should be
between 48HRC and 58 HRC.

From hardness measurement it turned out that the lobe hardness is 45 HRC,
possibly as a result of revision in which too much of the hard surface of the cam
is removed by grinding without surface hardening again.