A full-bodied square with a side of 20 mm was used, hardening was 1000-1100 degrees (dark yellow color of incandescence), cooling in water, tempering about 200 degrees (light yellow tint yielded), low-carbon steel, hardened but not heated water is a small effect is (hardening in oil in my opinion is generally useless for such steels).
Cutting a rod with a diameter of 8 mm - normally without problems, a 12 mm rod - cuts but dulls, but the blade as a whole can withstand, does not bend, and crack can not be too soft, if it exceeds the permissible load it bends and does not break.