Recently someone gave me a bar of mystery steel that had been sitting in their barn for many years. Despite the conditions, it had not rusted and was still fairly shiny ( it was not plated). I spark tested it, and it strangely produced almost no sparks. The few sparks it did produce were reddish-orange. It is attracted to a magnet, and is soft and easy to file. Today, I tried forging it. Oddly, it hardly produces any scale at all, and only at high temperatures (at about bright orange, it seemed).
I also drew a taper on the end and test quenched it it water. It did not harden at all and I was able to bend the quenched end of it over cold without it cracking. After this, I was satisfied that it was a decent material, and I decided to make a pair of bolt jaw tongs from it. It forged fine; it was just a little bit harder to move under the hammer than mild steel, but nothing like 5160 or anything like that.
After the tongs were done and I was just doing the final tweaking of the jaws at a low heat, one of the jaws broke right off. The material did not give any prior indication that it was prone to cracking in my earlier tests, but it did here. The grain structure was pretty large at the break; I wonder if all the heats while forging it grew the grain size and made it weaker?
I guess it was just another lesson on using mystery steels. Anyone know what sort of steel it could be, given the information above?