Mystery steel


New Member
I work at a scrap yard and have access to a lot of steel. The steel that I have tried is high carbon. But the problem is I don’t know what the number is. I did a heat treat to see if it would harden. In water . Not sure if will work or not . Any help would be appreciated. I think it did . It was 3/16 thick. Had a hard time trying to break it. Thanks Chris

Chris Railey

Such is the problem with mystery steels. Unless you have the capability to determine its makeup you likely will not know what steel you are using. This is the main reason most reputable knife makers will shy away from unknown steels. The other reason is that scraped steel may contain micro cracks and other problems that build defects into your work so no matter how good you are the steel may still fail. Let's face it, the steel was scrapped for a reason. All of that being said I am more of a blacksmith than a knife maker so I use re-purposed steels in tools and sometimes blades but ALWAYS for my own use only. I do not sell tools or blades made with re-purposed steel. Re-purposed steel is a great way to practice forging knives IN MY OPINION because you will learn many things turning it into bar-stock then into a knife. But when you are going to gift or sell a knife or tool I would always use new steel. Its very cheap insurance for your project.
Now for your water test: From your description IN MY OPINION and experience you have more of a medium carbon steel because you had to work to break it. But like I said, you will not know for sure because you do not know the steel's make-up. Most HC steels when heated to non-magnetic and quenched in water (if it survives the quench) will shatter like glass, even the thick stuff. I once did a demo where I heated a chunk of leaf spring from a school bus to non magnetic and quenched it in water. Then I placed it on my anvil and gave it a light strike with my hammer and it shattered like glass. I took a lawn mower blade and did the same exact thing and I could not break it even though it was thinner. Lawnmower blades are more of a medium carbon steel which will harden somewhat but they do not want them to break for obvious reasons so they are tougher and not as hard. So, in short practice on scrap but if you are going to gift or sell use new, known steel.