Subject: Re: Identification of Alloy

From: [email-masked] (Steve Rayner)
Date: Sun, 19 Feb 1995 12:54:02 GMT

In a previous article, [email-masked] (William E. Lee) says:

Might be nickel silver ( German silver ).

>I am an instrument maker at a med. sch. and over the years I have run into
>a metal often used in microscope, stereotaxic and manipulator parts that I
>would like to identify and find a source for. The material usually looks
>like it has a matt nickel plating, I suspect that it is plated, and the
>first time I had to modify some parts, I was "sure" that I was working
>with plated brass. However, when I drilled a hole into the piece, the
>color was the same all through. It works like brass, soft and easy to
>machine. When turned, it most often "peals" and breaks into small chips,
>although the pieces I have worked on are all a little bit different. It is
>unlike any "stainless steel" I have encountered. Any help would be greatly
>appreciated, thank, Bill
>

-- 
                                Steve Rayner.

---

From: [email-masked] (James Kirkpatrick)
Date: 17 Feb 95 14:14:17 MST

In article <[email-masked]>, [email-masked] (William E. Lee) writes:
|>I am an instrument maker at a med. sch. and over the years I have run into
|>a metal often used in microscope, stereotaxic and manipulator parts that I
|>would like to identify and find a source for. The material usually looks
|>like it has a matt nickel plating, I suspect that it is plated, and the
|>first time I had to modify some parts, I was "sure" that I was working
|>with plated brass. However, when I drilled a hole into the piece, the
|>color was the same all through. It works like brass, soft and easy to
|>machine. When turned, it most often "peals" and breaks into small chips,
|>although the pieces I have worked on are all a little bit different. It is
|>unlike any "stainless steel" I have encountered. Any help would be greatly
|>appreciated, thank, Bill

Identifying "mystery metals" is generally tough.  One major clue would
be whether it is magnetic or not (note that some stainless steels are
magnetic, some are not, and I believe some are depending on treatment).
If it is very magnetic, you might have a form of steel that has a small
fraction of lead added to make it easily machinable.

Some steels can be tentatively identified by the spark color and shape
when ground on a wheel.

You might be able to measure the density reasonably accurately.  This
probably isn't enough to ID it but to rule out some candidates.

Some materials can be identified by asking an old-timer :-)

If the parts look like they were die cast, it might be a zinc-based
"pot metal".

But I've never run across a general method.  I asked this once and got the
suggestion to run it over to the nearest lab and ask for an energy
dispersive x-ray analysis; this may actually be reasonable in a med school.
There are also the "spot" tests, described in books by Fritz Fiegl.

If there is an easy, general method, I'd like to hear!

Jim