Regarding the welding: with mild steel, the weld Is stronger than the steel. With alloyed steel, there will be problems with grain growth in the welded areas, inconsistent temper, and this steel is air hardening, so the welded areas will have areas of full hardness surrounded by overannealed boundaries. I'm not saying don't play with the steel you have, but be mindful of the limitations. Inspect the blade frequently, and I would be cautious re: letting anyone else use it. BTW, what filler rod did you use? I have been trying to learn more about alloy steel welding.