Re: [ihc] Front Spindles Heat treated?

["Jim or Ginger Aos" <jaos@xxxxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "John Hofstetter" <hofs@domain.elided>
To: "Jim or Ginger Aos" <jaos@domain.elided>; "James Lidberg"
<jameslidberg@domain.elided>; <ihc@domain.elided>
Sent: Sunday, March 14, 2004 1:10 PM
Subject: Re: [ihc] Front Spindles Heat treated?


> on 3/13/04 3:34 PM, Jim or Ginger Aos at jaos@domain.elided wrote:
>
> > The difference is in the heat treating
> >
> > Lt. straw             400 degrees F
> > Dr.    straw         450 degrees F
> > Lavendar            500 degrees F
> > Dr. blue              600 degrees F
> > Lt. blue               650 degrees F
> > Dull red on a dark day 1,000 degrees F
> >
> > These are approximate and are dependant on a failing memory, and this is
> > more than you asked for Jim A.
>
> So, Jim, these are the temps for annealing steal.
Not really;  True annealing is done by heating to the austenitic condition,
1350 F to 1700 F, at that temp. the carbon goes into solution with the iron
and the steel is unaffected by a magnet.  Then you slow cool it to about 200
degrees F taking about 1 to 6 hours depending on the alloy content.  The
higher the carbon equivalency the longer it takes.  Cooling to quickly is
quenching which causes brittlness or what is called, "file hard" or ,"dead
hard".  Normalizing heating to the same austenitic temp, but letting it cool
natural.

These colors are based on heating a part of the steel is ground or sanded to
a clean polished look.  Then as the heat is applied the surface oxidizes and
the resulting color is evidence of how hot it became.  The procedure for
heat treating is this;
Step 1 heat to austenetic condition hold that temp for a full minute.
Step 2 with the steel annealed do all the shaping, grinding, etc.
Step 3 Reheat as step 1 and quench cool rapid the higher the alloy the
slower the quench
one of the cheaper quickest is moving salt brine to the slower oils to
compressed air with all kinds of combos in between.  That will place the
steel in a martinsitic condition or dead hard.
Step 4 Do any finish grinding, polishing, etc. and use the shiny surface to
check the color for step5
Step 5 Draw the brittleness out by re heating- this is where the color code
come in caution if you over heat the process has to start all over with step
1
Step 5 Is also called drawing or drawing the excess brittleness, hardness
out of the steel.  This is also the final control portion hence the
fulfilment or temper step.

Is it reasonable to assume
> that Jim L's spindles (dark blue) got up around 600 degrees?

Correct
>
> Even though I've done a lot of metal work including annealing and
tempering,
> I've never given any thought to the color left on the steel after it
cools.
> Obviously, even if it works for the other colors, steel that has been
heated
> red hot isn't going to retain its red color, but ....

>
> What about the other colors? You mentioned file tangs, and they are
usually
> dark blue, left over from the annealing. ????

File tangs are soft because they are NOT quenched as the rest of the file
is, and the extreme hardness of a file does not need the last step.
>
> John
I could have made some technical errors here but this is the general
process.  If I left any with questions?  Please do as I requested my former
students and ask for clarification.  This brings back some good moments in
my teaching adventure.  For all on the list that have wondered how to
pronounce my last name, say the word close as in too close for comfort.
Then say the same word with out the cl.   Jim Aos     Cheers
> John Hofstetter
> www.goldrush.com/~hofs