I have been hanging onto this sheet of 3/8 aluminum for too long, thought I might get a few hundred for it (4x7 or so). It has no markings, is there any way to test aluminum alloy? If it was 6061 or something would it say so?
Need a pic of the surface cleaned with a detergent; no sanding or wire brushing..Odds are it is 6061 but yes normally it would be marked in ink..
Are the edges sheared rolled or sawed? If sawed with a round blade (looks like it was done on a table saw) it could be cast tooling plate which would be similar to 356 alloy. High dollar stuff, but like cast iron, it won't take bending. A high percentage of sheet is 6061, so if you want to guess... Other than that, it is pretty hard to tell without a hardness tester and a spectrometer.
Most shops just use it for non-structural stuff. Low load bearing brackets, panels, floors, etc. In a case where you NEED to know what it is, most shops would scrap it. Aluminum isn't like steel, where there is various different ways of "having a guess", by the above noted methods, hardness tester, grinding "spark" shape. Me, I used a "no-name" piece like that on top of my work bench where having a nice flat, sorta hard surface has served me well for over 30 years. Or, yes, you could send a piece of it out and have it chemically analysed to tell you what it actually is. But I doubt that cost would outweigh just using it for brackets, give it to a buddy, strengthen your garages walk-in door..! Mike
Cast tooling plate has swirl marks on the surface where its machined. Graded Alu is always stenciled 2024,7075,6061 is and 5052 and 3003 is not. also the graded alu when struck with a hammer has a sharper sound then the others dull sound
There is no way you tell by just looking at it unless there are some marking printed on it. The only way you can tell for sure is have a metallurgical lab do a spectrometer test which uses a plasma spark to measure the exact composition of elements. The other option is to take it to a recycling facility and they sometimes have a hand held gun which works very similar to the spectrometer and while not as accurate will get you very close to the chemical composition. As someone else said the measured hardness can also give you a clue. The hardness needs to be tested on a Rockwell Hardness Tester. Probably the most common aluminum alloy is 6061 T6. If it is 6061 T6 to hardness should be approximately 60 Rockwell “B” Scale (RCB 60). Aluminum sheet and plate are usually rolled so will have a smooth finish. The edges are typically sheared or cut but you cannot tell what type aluminum it is by the edge finish. Cast aluminum plate (356, 355, 357, etc.) is actually fairly rare unless cast for a particular application. I think your best shot is trying to identify at a recycling yard as mentioned.
See if you have a foundry or a big scrap yard around that has an in-house lab for testing if you really want to know. They might just do it for you as the testing is not a big deal but the tools etc are expensive. If your just getting rid of it for scrap the don’t stress about it .
Thanks guys. I put it on CL and someone has asked me if it was 6061. I can't tell how the edges are cut. Guess I will just say I don't know.
Well, speaking of alloys, I happened into a small space museum next to where I was getting a sandwich today. Space suits, rockets, etc. along with this meteorite. The description says "Campo Del Cielo, from northern Argentina, impact 6,000 years ago. Found in 1576". I pick up a lot of rocks on my property, one this size I would typically one hand toss out of the way. Not this thing! My guess was 50 lbs., which the two volunteers there said was about right. Whatever planet it came from is made of heavy stuff! Edit: I looked up Campo Del Cielo, sounds like mostly iron. Man, 100 ton meteorite crashing into Earth. That musta hurt. https://en.wikipedia.org/wiki/Campo_del_Cielo
There used to be a program on TV I think was called the Meterorite Hunters. They would travel to sites where there were documented meterorite strikes. They would walk around with magnets on the ends of sticks searching for fragments. They said they could find fragments by how they looked and if they were magnetic. Evidently the meteorites are valuable and easy to sell. I thought it was interesting but admit I can be a bit weird.
Running a file over the edge can get you close, as 6061 will mush over and leave some material, 2024 and 7075 will file harder and leave the edge clean. there is also a different feel when drilling, the harder 7075 and 2024 chips as you drill and the 6061 will pull a string. I work with aluminum every day, so much , I can taste the different alloys
I've got a couple of shift knobs I made from 3.8 billion-year-old meteorites. That's about a week and a half younger than Planet Earth. Unlike the aluminum sheet, you can tell a lot about each meteorite specimen just by looking at a fresh cut surface. The nickel/iron type, like mine, have a distinct structure called a Widmanstatten Pattern, named after the guy that first noted it. The pattern can't be reproduced in a lab or foundry because it's only formed by molten core material cooling slowly over millions of years, in 0 gravity, and total vacuum. I've got the pedigree papers on these pertaining to where they were found, etc. If you know of anyone who may be interested, I can be convinced to let go of one for one dollar per million years it has existed.
That sheet also could be 5056 or 4043 . With out any markings , seriously that sheet would only be a guess as to what it was is . Being outside in the elements that takes the value out of the sheet .
Was thinking: get some 'common' known sample pcs, 356 plate, 3003, 5052, 6061, and set up your own hardness, or 'drag' test. Use a magnifier lens. Then hit your unknown. How deep was the point? Or the depth and character of the furrow?
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