Alloy Analysis Tools

[awemawson]

In another thread the subject of identifying alloy compositions came up and I let slip that I had a couple of devices. I thought that this would be best handled in a new thread - so here it is!

Some years back I was heavily into metal casting and wanted to identify what I was working with. I went through all sorts of processes - even got myself a spectrophotometer (now disposed of) but came up with two handy commercial devices designed to do the very job.

A: An Analoy Portable Alloy Identifier

B: A Metascop Metal Spectrascope.


The Analoy Portable Alloy Identifier is a suitcase sized 'luggable' box of tricks that must contain an early microprocessor (never opened it up!). It works by striking an arc between the sample and a carbon / graphite point. The light from this arc enters an optical system that spreads the spectrum, and the critical lines in the spectrum are analysed for intensity. This is cogitated by the electronics and turned into a print out showing the individual metals as percentages. It also trys to identify the type of alloy from an internal list of the more common ones.

I last used this possibly ten years ago, and it's sat on various shelves in various workshops over that time as you can see from the pictures

[awemawson]

The base unit contains the power supplies and the printer as well as the microprocessor electronics. There is an umbilical cord tethering a hand held probe. The probe holds the graphite tip, and also the optics

[awemawson]

You hold the probe, rock it on the sample to strike an arc, and need to hold it for a certain time for it to gather sufficient data before it spits out a printout.

These units have been sat in my unheated welding shop for the last six years, so I'm going to leave them open for a few days in the heated main workshop before powering up. Looking at the paperwork it seems it was 2004 when I last used them 

In the box was a print out of my last sample all those years ago.

I have two, as when I acquire complex kit I always try to get spares if at all possible

[awemawson]

The Metascops had been in the main (heated) workshop so I was happy to power one of them up

[awemawson]

A less sophisticated device than the Analoy this time you do the analysis. Again you rock it on the sample to strike an arc, and looking through the eyepiece you see spectral lines, the wavelength of which you can measure using the tweaking knob on the side.

Once more - I have two of them - my usual obsession with spares - but number two is a sad example compared to number 1. It obviously started out in a much less flashy , more utilitarian, box, and has had a harder life.

[awemawson]

I powered #1 up and struck an arc on a piece of galvanised plate. I wish that I could show you the spectral lines, they are really very attractive as well as interesting. But despite my best efforts couldn't capture them on a photo. With a bit of juggling I did manage a shot of the arc.

[awemawson]

Well I'm pleased, and frankly rather surprised, to be able to report that BOTH Analoy Alloy Analysers worked - I'd left their cases open in the heated workshop to give the innards a chance to dry out having been stored in unheated space.

On the first one, the ink had soaked into the paper roll, but unrolling more paper and cleaning up the mess from the printer cured that. I decided to clean the little window that  shields the arc from the optics, and forgot how delicate it is and put my tissue covered finger right through it  Then I remember that this wasn't the first time I'd done that, and sure enough tucked away in the box was a carton of microscope 'slide cover slips' - basically a square of very thin glass - that I'd bought last time to replace the window - nine years ago.

The foam case padding is all crumbling as it does after a few years, but astoundingly both these testers work fine.

Andrew

[Pete.]

That's pretty cool. How far can it narrow the analysis down - I mean can it tell between 304 and 316 stainless, or can it just identify the material as stainless etc, or a particular series like 300 or 400 etc?

[awemawson]

I'm not entirely sure Pete. I have a feeling it's meant for aluminium / magnesium / zinc alloys though it does test for:

Al - Aluminium
Si - Silicon
Fe - Iron
Cu - Copper
Mn - Manganese
Mg - Magnesium
Cr - Chromium
Ni - Nickel
Zn - Zinc
Pb - Lead
Li - Lithium

Not at all sure how it does it's analysis once the measurement has been sampled. For instance I struck an arc on a lump of lead, and it came up 'No Base Metal' - so it must be making assumptions on what is likely rather than just a quantitative analysis of what is there.

Turns out it has an 8085 microprocessor, so if I ever get a few free weeks I'l see if I can disassemble it's eproms and try and get some clues as to what it's doing.


Andrew

[S. Heslop]

Thanks for showing these. I always wished there was more easily available literature on how scientific instruments are actually constructed, and not just on their theory and operation.