Subject: Re: colour quenching chart

From: [email-masked] (DFogg)
Date: 19 Feb 1995 09:59:29 -0500

Color can vary depending on ambient light in the shop, perhaps a better
and more reliable way to judge hardening temperature is to use a magnet.
The steel will become non magnetic at or around the hardening temp. and
can be safely quenched at that temp.

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From: [email-masked] (william thomas powers)
Date: 19 Feb 1995 13:53:58 -0500

In article <[email-masked]> [email-masked] (Elisabeth Czerwinski) writes:
>Does anyone know of a chart that compares the colour of forged steel just 
>before quenching with its resultant strength or brittleness?  I'm trying to 
>track this down for a locally trained blacksmith at a small historic village 
>museum.  

Its a bit more complex than that.  For the straight steels, (low alloy),
and what you would be using in most "historic" venues; the correct temperature
to heat before quenching, is the Curie temperature---when the steel becomes 
non-magnetic.

Upon quenching at this temperature the hardness and brittleness is controlled
by: 1) the quench medium--oil, brine, water and 2) the carbon content of the
steel, 3) the thickness of the steel being quenched.

I would really suggest that you get a hold of _The Modern Blacksmith_
by Alexander Weygers, isbn 0-442-29363-1, It is probably the best
beginning blacksmithing book I have ever seen and has a Colour chart
of both forging and tempering colours on the back cover.

And remember if someone tells you that that there is only one drawing
colour for a type of object--no matter what the alloy is--beware! They
don't know what they are talking about. (eg: you make 2 knives; one from
1075 and one from 1095--temper them to the same colour and one will be
too soft or too hard if the other is "just right").

Thomas, who got to forge all afternoon yesterday; bliss!
Columbus ohio