I am a heat treater in Detroit MI. If any of you guys want to try a blade that is surface hardened, I would be glad to process some for you free of charge. The process is called ferritic nitrocarburizing and hardens the surface only. It is important to leave the core soft to keep ductility for safety. I am trying to research the benefit of this process on mower blades. All you have to do is supply the baldes and pay for shipping.