D. Taylor - I like Ravenshear's books, though I suppose I might say the metallurgical parts differently.
OK, you asked for a metalllurgist's opinion (this is where Wife makes slashing signs across her throat)
Strictly speaking, metals do not HAVE molecules. Metal is a bunch of individual atoms arranged in an orderly (more or less) pattern called a crystal. In English we like to call those crystals "grains". Germans say "korn". Little grains are good, big grains (crystals) are usually bad, make the thing more likely to crack, break in use.
When you forge a steel widgit parts of it are hotter than others, some parts get worked at a lower temperature than others - like, as the thing is cooling. Some areas have been so hot they grow very large grains.
You've heard someone say "...it crystallized and broke" Well, it does look like that. If the crystals are large enough that you can see those shiny facets on the fracture surface, they are much too large. If the steel has been treated correctly, and you chose to break a piece, the fracture surface will have a silky gray appearance.
For hundreds of years people have been judging various quality aspects of steel by hardening & breaking a piece. That fracture surface tells a lot. In Olden Times there used to be nice sets of broken bars of tool steel used as standards for how steel of various grain sizes appeared when broken.
But you have some enormous grains here and there, because you forged it. Dag-gone. So do as someone earlier in this thread said, "normalize" your forging. That is, heat it up to maybe a cherry or hardening red, then just lay it on the ground to cool naturally. That is, after all, the Normal way to cool a piece of metal. The nice thing about steel is that it grows new grains in this process, and unless you heated it too hot, they will be finer grains than what you started with. Then clean off the scale and a few thousandths of surface that have had the carbon burnt out of them, and heat treat it as a spring. Lots of discussion of this, I'd try Ravenshear.
Normalizing (or maybe annealing) a steel forging is Textbook Metallurgy. And it works. As a skinny black haired kid during the JFK administration I managed to convince the product manager at Black & Decker to do this to his metal cutting tool bits, things to cut sheet metal using an electric hammer. He did so, then tested one of the regular heat treat, and one done as I suggested. Mine worked. Heh, heh the old style broke and cut his thumb.
Envision Wife making "T" signs with her hands, or throat slashing motions. OK, I'll stop.
(if you see crystals on any broken steel surface, them there grains wuz just too too big. Normalize the thing).
