I do a lot of scrapping and would like to be able to separate stainless steel from regular steel. The magnet test doesn't always work since stainless can be magnetic, but what are some ways that I can for sure tell the difference? Or even something like a sound that they make that may help me to tell the difference.
Stainless steel uses chromium in its mixture to thwart the affects of corrosion. General steel, or carbon steel, is generally almost completely iron and is used for far greater applications than stainless steel. Stainless steel is used mostly in kitchen appliances, utensils, etc... The best thing I can come up with is to find a way to measure the chromium content of the steel you are looking at. If it's around 3% chromium, it's probably standard steel. If it's somewhere between 10-15% chromium it's probably stainless steel (or even 4% plus). I can't tell you a fast and quick way to test the steel because from my research, it appears there are as many grades and allows of steel as there are uses for steel! There is one test I've seen for home testing surgical steel which is a higher grade stainless steel, that is to put scotch tape on one section of material then soak it in water for a 24 hour period, then let it air dry for 24 hours. You remove the tape and lightly polish the exposed areas to see if there was any discoloration or pitting on the exposed area. This test is mainly for surgical steel jewelry, however stainless steel is supposed to resist rusting more than standard steel, hence it might work for other steel types as well. You may have to read some of the other links below to get some other ideas on how you can test steel to see if it is stainless.
If you do a lot of scrapping. It is best to get XRF handheld metal analyzer. But they are quite price. Around USD 40.000 upwards! Magnet may only help you sort SUS304/316/201 from SUS430 and metal. But then there might be other alloy. Thus it is best to get XRF analyzer if you feel it is worth the price.
Stainless steel should be non-magnetic.
