Practical identification of stainless steel 304 vs 316

A. Common trick used by myself and a few other blacksmiths for recognizing high, mid, and low carbon steels. Take it to a bench or angle grinder [on eBay or Amazon] , high carbon will produce lots of sparks, mid will do less, and low will produce very little.

Take a steel you know the carbon content of and use that as a gauge.

Good luck

A. I remembered something that may help you a bit more in identifying steel compositions. www.iforgeiron.com/Blueprints/BP0002Junk_Yard_Steel/BP002_Junk_Yard_Steel.htm. This will give you a basic idea as to what steel you are working with, I have found similar tables published in a few other blacksmithing references as well.

A. Hi Mark. A portable x-ray fluorescence alloy sorter / scrap sorter [on eBay or Amazon] seems to me may be the most practical way to know in this instance. Good luck.

Regards,

A. Hi Mark. We like to explain things here with barnyard examples and barnyard metaphors because our international and English-as-a-second language readers then have no trouble following the discussion. It's easy to sort chickens from horses by simply counting the legs on the animal; but if someone throws some cows into the mix now you have a problem.

Similarly, there are inexpensive chemical tests to distinguish 316 stainless steel from 304 stainless steel by, for example, looking for molybdenum in the stainless. There are spark tests as well. These tests are fine for sorting known materials. But the only way to know for sure that something is 316 stainless steel rather than anything else in the world is if it matches the chemical analysis for 316 stainless; so I don't know a way to be really sure that an unknown material is 316 stainless except with a scrap sorter x-ray fluorescence machine. But, yes, if the pipe passes a simple 316 test, it is most likely 316.

Regards,

A. I found a Koslow kit, online, that looks like a good bet. Thank you very much for your help!