[ciccioic]

Hello! Is there anybody who can explain me something about the progressive induction hardening? The question is:
when I use the progressive induction hardening on a ring (made in appropriate material, in quenched + tempered state), there is a zone (at 360°) where I have to pass over an already hardened part for "closing the circle". What happen in the "re-hardened" zone? Will the hardness increase or decrease? Will the deep of hardness increase? What about the residual stress in that zone, will be better or worse? And what will happen to the close zones which will be wormed for conduction? Will they be anelled or tempered?

Thanks a lot for the answer.
.m

[eugenedakin]

Hello ciccioic,

It really depends on the type of metal and the metal phase you are trying to create.

Progressive hardening is used to harden areas that are much larger than what can be used with spot hardening.

As an example, here is a link to a phase diagram over different temperatures: http://www.roymech.co.uk/Useful_Tables/Matter/Phase_diagram.html.  The type of surface and deep treatment of metal depends on the heating temperature, cooling rate and time for this material.

I hope this helps.

Sincerely,

Eugene