So recently I was involved in a debate about steel, more precisely, modern carbon steels used in knife making. This may seem like a bladesmithing topic but I think it applies better to general forging of modern carbon steel. at any rate its a good study of material science.
It started as I overheard some general conversation about forging a complicated knife shape vs stock removal to achieve the same shape. the argument was that in a "modern carbon steel" it dosnt matter whether you for
Yup, use mild steel.. Save that for other projects.. I will be putting out a "How to" video on figuring out mystery metal and how to use it but it's not going to be ready till mid summer..
Ideally you need to figure out what metal it is before you use it.. without testing it myself and not knowing what temp you forged/bent it at from your description, I'd guess it's an air hardening steel..
Looks like a spring from an old hay rake..