Case hardening layer running out in fillet
Case hardening layer running out in fillet
(OP)
Hi All,
I have inherited a design of camshaft that has induction hardened cam surfaces with a case depth of ~2mm. The shaft diameter lies ~3mm below the base circles of the cams with a generous fillet radius transitions between the shaft and cams that run out just below the base circles. This means that the case layers run out (transition back to parent metal) part way through the fillets. Is this an acceptable condition or could this give rise to a risk of failure? Is there anything that can be done in manufacturing to mitigate any risk?
Many thanks,
Dave
I have inherited a design of camshaft that has induction hardened cam surfaces with a case depth of ~2mm. The shaft diameter lies ~3mm below the base circles of the cams with a generous fillet radius transitions between the shaft and cams that run out just below the base circles. This means that the case layers run out (transition back to parent metal) part way through the fillets. Is this an acceptable condition or could this give rise to a risk of failure? Is there anything that can be done in manufacturing to mitigate any risk?
Many thanks,
Dave





RE: Case hardening layer running out in fillet
The operative word here is "could". If these cams routinely fail at this location, this could be a reason. However, is it quite possible that the fatigue loading in this area does not reach critical levels, so while in some designs this situation may be dangerous, in others it is not.
You say you have inherited this design. Do you have any history with the longevity of this design? Are fatigue failures common? If not, I wouldn't worry about it. Even if this currently is not a problem, it could become one if the loading of the cams increases (which is why design changes should be fully analyzed before putting into service).
rp
RE: Case hardening layer running out in fillet
RE: Case hardening layer running out in fillet
RE: Case hardening layer running out in fillet
As others noted, this condition does not seem to present serious problems since many camshafts are successfully produced using this approach. However, as with any other case hardening process involving heating and quenching, you should pay attention to details in your part design, process and heat treating equipment.
RE: Case hardening layer running out in fillet
Thanks for all your replies. I'm sorry I've not thanked you all sooner, I've been off work. The information you've provided will be really useful.
Dave
RE: Case hardening layer running out in fillet
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