The machinery hand book, at least mine does, has a section on what different steels are, gives the asme designation of drive shafts, leaf springs, torsion bars etc of the parts of heavy and light machinery.
I have made things from automobile leaf springs, old one piece chainsaw bars and lawnmower blades quenching in water and heating to a yellow for tempering. More specifically, roughly tempering, ,,,Not necessarily hammer forged, but cut to shape with oxy acetylene ground, shaped and bent with heat etc. I made new shear blades from ford light truck springs for a heavy duty manual rebar cutter that have held up for years. Chainsaw bars are mostly three laminated layers now. Lawn mower blades have worked very well for several projects or repairs for me.
My forge is a propane bottle, a propane weed burner torch and fire brick or my oxy rig,
chuck