A little metalurgy for the morning. Just thinking it through. Divergent information welcome.
All steel objects will deflect (bend/stretch/ compress) when a load is applied. The amount of deflection for the load applied is called modulus. Soft and hard steel have nearly the same modulus; this is a counterintuitive point. For example, if I made two identical spring shapes, one of soft steel and one of hard steel, they would perform basically identically as long as I did not deflect them more than the plastic limit of the soft one. However, the hard one would continue to function at higher loads and deflection after the soft one failed in plastic deformation.
Applying the above to an action, the soft core of the action would have to be deflected beyond its plastic limit to have strengthening from the hard case layer. IMO, the core has much more strength than the case. So, if the action were bent beyond the core's plastic limit, the core would overpower the case such that the case could not force the action back to original dimensions. Only if the case layer could force the plastically deformed core back into shape would the case actually add strength beyond its value if soft.
OK, floor is open.
