Re-hardening a blade

[nelsonchenknives]

Hi all,

I'm back with another basic heat treat question. I've been working on some hamon blades, and from time to time, I'll fail to get a soft spine and thus need to re-do the heat treat. My question is do I need to normalize the already hardened blade before re-hardening the blade? and if so, what kind of normalizing cycles should I run for 26c3 steel? the blade is a flat blank at 65 RHC through out, no forging or grinding at all.

I asked my material science friend, and he's leaning towards not doing any additional process and go straight to austenizing temp and then quench, but I thought I would get a second opinion here.

Thanks!!

 

[inferno]

no. just re-ht.

the more times you HT the finer the grain will get and at some point it will get counterproductive and you will start losing hardness and toughness. i usually do 2 quenches. because it simply takes 1 to dial **** in and then a real one. i'm working with gas.

 

[nelsonchenknives]

that's good to know.

i've been running one or two normalizing cycles in between, so i'm glad i can cut some unnecessary steps out of my process.