Thank you, Chris. What Chris said about a certain item automatically equaling a certain alloy is very much my position as well, and this situation is only getting more true as time goes on and manufacturers find more cost effective ways of producing those items. But it goes so far beyond this in complicating working the steel.
To give you an idea of how tricky it can be, back in the early 80’s, when I was starting out, I too was bitten by the scrap steel bug that is almost universal among new makers, I later realized how much time, effort and supplies I sacrificed to that huge wrench in my learning curve. After that, I have always worked with the best, known steel that just a few bucks will buy (the steel really is the cheapest part of the entire knife).
But even working with a brand new bar of steel, all pretty, clean and labeled, slight deviations in the chemistry would occasionally have me troubleshooting my heat treatment. For the past couple of years, I have been buried in research and testing of the most common bladesmithing steels to develop guides to the way we work them, and until now I really had no idea how critical this is. In my research I have lost months of lab time when even that shiny, labeled, bar of steel turned out not to match the chemistry I thought it was. So, I now only buy steel that includes the spec sheets, and analysis of that specific batch.
But let’s say you spend the $100 to a zap a spectral on that scrap item, you now have the chemistry, but you are still missing things that can be just as critical. First, the spectral will only give you chemistry, it will not give you anything about the physical condition of the steel- inclusions, grain size, microstructure, or those very valid concerns Chris brought up about micro-defects from its previous life. What it also won’t give you is the thermal history on that piece of steel which has essentially made it what it is today, and that history will play a role in how you treat it and the outcome of those treatments. It is almost like alternate timelines in Science fiction. For the testing that I am doing, I can’t just do a batch of samples that are hardened and tempered using different methods, I have to do a batch for each of those methods that was normalized at several different temperatures and annealed with differing methods because each will respond differently to the temperature and time in the hardening heat. Eventually the number of possible paths of thermal history becomes infinite, and I am forced to settle on several of the most pragmatic ones.
Now, do I have a scrap pile out back? Sure I do. I use it for all kinds of forging practice and items that do not require a heat treatment. And now is also the time for me to include the same exception that I always do- there are times when the sentimental or historical significance of the piece outweighs the need to optimize the performance, e.g. a knife made from Grandpa’s favorite file, a blade made from World Trade Center steel, etc… I will also sometimes work with historical processes to produce historical materials, such as bloomery iron or blister steel, and while I still do a whole lot of lab work to know that material, it will never compete with a known, modern, alloy. But it doesn’t have to, its value is in another area.
Sorry about the long-winded reply but I wanted to clarify the specific do’s and don’ts I was suggesting. I also apologize for hi-jacking a thread that should be about any number of helpful tips rather than my over worded concerns.