I picked up several rods that seem to be made from stainless steel (as everything else at that place had specks of rust).
However, they are slightly magnetic. Clearly much less magnetic than regular steel, but magnetic enough to make magnetic darts barely stick to them and not fall.
What material can it be?
The rods are about 1 3/4" diameter and several feet long.
The 410 SS sheet that I have been able to test would hold a magnet about as well as mild steel. My guess is 304 that was substantially work hardened from cold rolling. I've seen plenty of 304 nuts in sizes from 1/4-20 on down that would stick to a magnet from the work hardening due to forming.
Those two are the austenitic grades that gain the most magnetic permeabiity from work hardening. (They start off in the annealed state with virtually none.) And austenitic stainless grades are by far the most common types.
Almost all other series' of stainless are much more magnetic. It's a matter of their ferrite or martensite content. In austenitic grades, you produce some martensite when you work it, converting a bit of the austenite. But not much.
There are a couple of new ones I saw at Fabtech -- Thermo Scientific Niton XL5, and Rigaku Katana 6063. I think the Niton is around $15k. I don't know the price of the Rigaku.
It depends on what you'll do about it, once you determine the alloy. If you're just trying to sort scrap, knowing whether it's 302 or 304 generally won't make any difference -- unless you're selling scrap by the ton to a premium scrap dealer, who will give you more for single-alloy scrap. That's essentially what Ford is doing with their aluminum-body scrap.
For what you probably need, I would think that spark testing and/or compressed-air testing would be plenty accurate enough. YouTube is good for showing you what to look for, but the ideal is to have some known samples you can compare to the unknown metal you're testing.
It doesn't hurt to know standard applications, either. For example, if you have a pile of architectural-trim stainless, count on it being basic 18-8 (grade 302), and not ferritic or martensitic.
I see Ebay has some used for $5500 to $9,000, plus there is a $40 service to analyze samples for you. Although, I think it is overseas, the English seems to be a second language. There are other services. Mikek
You can get an analysis done for around $50. That seems to be the going price. If it was for a big load of scrap, and if it only came up once in a while, that would be the way to go.
Again, though, someone like Iggy has to ask what the value is of knowing the alloy with that much precision. With some experience and some good test samples, you can do a reasonable job with spark testing.
I've never seen compessed-air testing done, but that's another option, and supposedly it is a bit more accurate than spark testing with a grinding wheel.
I've been thinking that he might like to know the alloy *before* he bids on the lot -- and they are unlikely to let him take a sample to have analyzed. The gun would give the answer very quickly -- and unlike taking a portable grinder to the lot, would be less likely to get him banned from the auction site. :-)
How does the compressed-air test work? Any web site someone knows about?
O.K. Another thing that the auction site will probably object to, then. :-) This leaves the gun as the least obtrusive approach.
Thanks!
Understood. Somehow, I don't think that the auction site would be happy at Iggy (or anyone else) aiming a torch and compressed air at what is for sale. :-)
I'm sure that Iggy has this all figured out from the discussion, and knows what is practical for him to do, but my guess is that he's going to eyeball materials and make a rough estimate and a judgment about buying them, and then -- perhaps -- try to figure out the alloy before he sells them. In this case, for example, he was trying to figure out the material that constitutes the bars he already had bought.
I don't know that business works these days, but I do know that single-alloy purshases used to be for relatively big trades, in ferrous metals. In our shop in Princeton, we had a barrel for stainless turnings, and it was a mix of 304, 316, and some unknowns we got from customers. We weren't going to get more for them by separating the grades.
In aluminum, however, we had one barrel of 2024 and another of 6061. We DID get a premium for keeping those two separate. 2024 will contaminate 6061 with copper; it contains around 15 times as much as
6061 does.
In stainless, I think they just dump the grades all together and remelt, and then de-carbonize the batch to get it down to 304 or 316 levels. That's how they make 304 out of 302 (or general 18-8), to begin with. Alternatively, they could make it all 302 and sell it for making kitchen flatware and architectural shapes. I have heard of that being done.
So there didn't used to be premiums for separating austenitic stainless grades. Maybe they're more sophisticated today; I don't know.
Interesting. Prices may come down in a couple of years. One of the analysers Ed mentioned is a xrf. But the other one is a laser induced breakdown spectroscopy (LIBS) I really have no clue, but suspect the LIBS might be cheaper to make.
I think some of the problem of finding something is many that posted them have passed and their web pages are down for non-payment. And many changed sites due to company changes. The Metalworking drop-box is one as example. Now not on a company server, but on a private one.
My scrapper uses an XRF - but the settings for this and that odd Molly or whatever is so high it sees only Iron when looking at ballistic steel. I finally just hid the expensive steel under the other A-36. It weighs many times that of A-36 due to the high content of heavy metal (not lead) and they pay for the price and get it mixed in.
When I take in Nickel or copper - then the XRF is useful.
Mart> On Tuesday, February 16, 2016 at 12:12:56 PM UTC-5, Ignoramus21249 wrote: >>
But the other one is a laser induced breakdown spectroscopy (LIBS)
I really have no clue, but suspect the LIBS might be cheaper to make.
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