I've looked at this thread several times over the last couple of days, and hesitated about responding to it, but I think a point needs to be made about using "recycled/scrap". It's not a knock on anyone who does it, but more so a warning....
There was a time when we could find information that indicated specific items of steel, and the type of steel they were made from. That information started to be outdated about 10-15 years ago. As manufactures sought ways to reduce costs, and increase profits, a trend of final product specs took over. Basically what that means is that manufactures no longer specify the steel type (at least for most), but rather send the required performance specifications of a given end product, and as long as the item meets the MINIMUM end use specifications, the cheapest material (steel) is used. There are of course some exceptions, but by and large, it's nearly impossible to correlate an object/part with a specific steel type these days. In many cases the steel type even differs in the same item from production run to production run.
While it's still "fun" to give new life to an old item by turning it from a whatever, into a knife blade, it's an unknown, that requires a lot of time, effort, and experimentation to get it right. Which, in most cases must be repeated each time recycled/scrap materials are used for a knife...even if the "item" used is the same. That's the reason that many of use are always recommending the purchase of "new", "known" steel.