Aaron, I do not agree. Vacuum heat treat will reduce surface scale but is
very expensive. Machining after heat treat removes that issue. We heat treat
4130/4340 for aerospace everyday, never vacuum.
Mark
.----- Original Message -----
From: "Aaron Johnson" <fpspitfire37@msn.com>
To: "'MARK J WEATHERS'" <markjwea@email.msn.com>; "'Joe Curry'"
<spitlist@cox.net>; <fot@autox.team.net>
Sent: Thursday, July 15, 2004 9:07 PM
Subject: RE: Axle Steel
> Also remember that chrome moly steels will need to be vacuum heat treated
> rather than carburised.
>
> I have a couple of other recommendations for materials...i just need to
grab
> the notebook from the box that is packed for moving...
>
> Bloomington Illinois here we come.
>
> I start work at Caterpillar on the 2nd...hopefully the racing programme
can
> survive the move and I can get the car back together for the regional at
> Blackhawk in October.
>
> Aaron
>
> All the best
>
> Aaron Johnson
> #38 F Production Spitfire Mk4 Oregon Region SCCA
> http://www.geocities.com/spitracer9
>
>
> -----Original Message-----
> From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
> Of MARK J WEATHERS
> Sent: Thursday, July 15, 2004 03:59
> To: Joe Curry; fot@autox.team.net
> Subject: Re: Axle Steel
>
> Joe, I would recommend chrome moly steel personally, that is what I chose
> for the uprated axles I am selling. Specifically 4130 or 4340 steel, which
> can be hardened to 180ksi ultimate tensile strength and still retain the
> ability to stretch a bit rather than fail catastrophically. We make a lof
of
> critical aerospace parts from it. It is going to be cheaper than 13-8
> stainless which has even better properties. One caveat, these alloys do
not
> through harden well, that is the center and outside will be different, and
> they move when heat treated. You will have to specify where on the blank
you
> want the hardness checked (may have to cut one up) or.... rough machine,
> heat treat and then finish machine. That is a lot of material to remove
but
> it cuts well, actually better when hardened. There are more expensive
> choices still, such as Maraging, titanium, etc. but unless you recently
won
> the lottery chrome moly is a better choice.
>
> Mark
> ----- Original Message -----
> From: "Joe Curry" <spitlist@cox.net>
> To: <fot@autox.team.net>
> Sent: Wednesday, July 14, 2004 5:18 PM
> Subject: Axle Steel
>
>
> > All you metallurgists out there, I need some help.
> >
> > In trying to get my stub axles built, I am seeking recommendations for
> > the type of steel stock from which to turn down the shafts I am
> > designing and afterwards have them heat treated. So I need stock that
> > is strong and will take heat treatment to make a part that will hold
> > up to the rigors of independent syspension.
> >
> > I am not familiar with all the specs of the various metals so I am
> > relying on the wisdom of this group to provide not only a
> > recommendation for the type to use and also any sources for the blank
> > material from which to machine them.
> >
> > I am thinking that I need to start with round material 5" in diameter
> > and about 7" long for each axle.
> >
> > Thanks in advance,
> > Joe (C)
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