Klarinet Archive - Posting 001359.txt from 1997/08

From: "Brian Ackerman" <ackerman@-----.uk>
Subj: Re: Blue steel vs. regular
Date: Sun, 31 Aug 1997 20:50:09 -0400

> Gary wrote:-
> Blue steel, as in blue steel springs, is steel that has been treated with
> either hot or cold bluing. The same stuff they use on guns to help retard
> rusting. It is only a finish.
-------------------------------------------------------

Blue steel springs are the traditional type, as opposed to stainless steel.
They might be liable to rust, but are superior to stainless steel and give
a good response without being sluggish, and are found on most good quality
instruments.
Although the bluing does help to prevent rust, it is actually an essential
part of the process and is certainly not just a finish. Let me explain:-
High carbon steel can be heat treated. It is first heated to red-heat and
quenched. This makes the previously soft steel very hard, but it is also
very brittle and of little use. It is further heat-treated to a lower
temperature, which gradually brings down the hardness and reduces the
brittleness. The higher the temperature the softer and less brittle it
becomes, until it is eventually in its former soft (annealed) state.
As the temperature is increased, the steel changes colour, going from straw
to brown and then blue - so the colour is an indication of how far the
heating (tempering) process has gone.
The colour and degree of tempering will be governed by the steels final
use, so knives, for example, would be straw as they need a keen edge, but
bend it and it would break (it is harder but also brittle).
Obviously if clarinet springs were tempered the same as knives they would
be useless as they would break. The correct temper for springs is blue.
They are still fairly hard, but can be bent without breaking.
The blue colour is left on for three reasons. 1- it looks nice. 2- it shows
it has been correctly hardened and tempered. 3- it helps to prevent rust.
Finally, it is the same as "regular" steel. Stainless-steel would never be
described as "regular".
Brian Ackerman