Strange discoloration after hand sanding

[killthelights]

Ok this is not uncommon for NJSB. It’s actually quite common. And no it’s not ok, I would email them and have them replace it or refund you. That spot will not harden no mater what you try. Here are a few pictures showing a few of the blades I have come across that had this issue. So don’t feel bad a have a folder full of customers that got bad steel from NJSB, your not the only one.

You're not the first person I've heard this from but you're the first per person who heat treats for a living that i've heard it from. So while I'm sure my HT skills could use some improvement, that does make me feel better about it. Thanks! Also I think I'm done with 1095 all together. So many other steels out there that are not nearly as finicky.

 

[tkroenlein]

Standard heat treat. Using an Evenheat oven I put blade in at 1300 ramp as fast as poss. to 1475, soak 10 min, quench in Parks 50.

Why the ramp? How long does the ramp take? 1300F is sufficiently low to begin spheroidizing isn't it?

 

[Drew Riley]

Standard heat treat. Using an Evenheat oven I put blade in at 1300 ramp as fast as poss. to 1475, soak 10 min, quench in Parks 50.

Why the ramp? How long does the ramp take? 1300F is sufficiently low to begin spheroidizing isn't it?

I'm curious why the ramp as well.

 

[killthelights]

I'm curious why the ramp as well.

Mainly just info I've gotten from Kevin Cashen's site that's always served me well before.

 

[Stacy E. Apelt - Bladesmith]

The ramp takes the blade from sub-critical to the austenitization target. There is no need to do this slow. Most folks just put the blade in the 1475°F oven and start the timing count when the oven rebounds. By doing it as a programmed step from 1300 you get the 10 minute count to start as part of the program. I doubt it will matter which way you do it.