Case depth and modul
Case depth and modul
(OP)
Where can I find relation between the modul and the case depth for the calculation of a case hardnening gear?
Thank you
Thank you
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RE: Case depth and modul
ISO 6336 -5 has equivalent data.
These are general figures which work reasonably well but the most rigorous method is to calculate the depth of maximum sub-surface shear stress and then determine the depth of case necessary to contain the stresses.
RE: Case depth and modul
RE: Case depth and modul
I understand the most rigorous method but it seems that most of the time a modul is chosen without consideration of the case depth. As if the case depth is only a matter of the thermal treatment.
Normally, the depth should be chosen to be twice the depth of the maximum shear stress like for bearings.... is it true for gears?
RE: Case depth and modul
The general equation for carburized case depths in ISO 6336-5 is optimum case depth = 0.15 x Module for tooth sizes between 2 and 10 module. This is a metricated version of the AGMA 2001 case depths.
RE: Case depth and modul
According to MIL-STD-1878, CARBURIZING, GASEOUS ATMOSPHERE PROCESS FOR "For gears, general practice is to specify effective case depth as measured to Rockwell HRC 50, equivalent at the pitch circle contact point of tooth"
According to MIL-S-12515C, SURFACE HARDENING: FLAME AND INDUCTION (FOR FERROUS ALLOYS) the effective case depth depends on the carbon content of the material,
for 0.28 to 0.32 35RC
for 0.33 to 0.42 40RC
for 0.43 to -.52 45RC
for 0.53 and over 50RC
RE: Case depth and modul
RE: Case depth and modul
You are right in that more is not
necessarily better. I assume the max
is based on Jominy Tests for typical
materials. I would assume optimal
could be calculated by examining the
subsurfaces stresses caused by your
max load conditions. Do not have that
standard. Wondering if they give
suggested values where loads are light
but you are looking for high endurance
values. Are the values based on 48Rc
or 50Rc? I know the 48Rc value was used
in Europe for the case transition depths
in the past.
RE: Case depth and modul
Sorry! - long explanation for a simple question.
RE: Case depth and modul
And praticaly, is the maximum case depth an emperical result to avoid the case-core separation or a result of a physical model of the phenomenon?
RE: Case depth and modul
Thanks for your explanation. It was not
too long. We normally induction harden,
so come from a different background and
way of thinking about case depth.
RE: Case depth and modul