The vanadium is your friend with this steel as it really does restrict grain growth even if you get too hot in spots. Getting too hot not only causes excessive grain growth it is counter productive because the blade won't harden up like its supposed to and will be softer with brittleness. At least if you don't get hot enough it's softer, but not brittle.
I know you don't have much experience with colors, but you said you normalized the blades, how? It takes a temp of 1600+ degrees to normalize with a long, slow cool down, how do you know you achieved normalizing temperature? I ask because if the blade doesn't harden again you may need to normalize it again. Actually if you did achieve 1600 degrees you should have quenched it. lol
Seriously if you overheated the blade you could have seriously caused it to decarb. My apologies for not seeing it before, did you just heat the blade until it was yellow hot and then let it slow cool and how did you cool it? Plus you did it three times? I should have paid more attention. If a second ht doesn't harden the blade I'd toss it and try again with a new blade because the decarburization may be too deep to just grind off, start fresh. I hope you didn't use up all your stock.
This is a simple steel to ht and you should have achieved some hardening, the welding magnets are powerful enough that they still would have grabbed hold if it was below 1420 degrees. Note if you achieve nonmagnetic, but drop below that temp the steel remains nonmagnetic down to a lower temp, I'm not sure what that is exactly, but I've noticed it in my forge before. Anyone know exactly what it is?