1095 brine quench

J

James Hall

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Sep 18, 2013
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I'm on my third attempt making an 8" chisel ground gyuto from Aldo's 1/8" 1095. My first attempt warped pretty badly, and the other two cracked in water in a magnificent sori of destruction.

I finally smartened up and have two gallons of a 9% brine solution dissolving, to which I'll add some dish soap. I triple normalized with a torch last night, stepping from non-magnetic to darker non-magnetic temps. I used a torch because I'm becoming wary of my diy kiln, which may have caused some minor decarb last time.

I'd like to hear your thoughts on an interrupted edge quench for this knife, 2 seconds in and 2 out. I'm trying to be extra cautious this time because I think my other mistakes could have been preventable. I also sanded to an even 320 grit, and slightly radiused all sharp corners. Also FWIW, my other attempts were with a clay coating.
 
James Hall said:
I'm on my third attempt making an 8" chisel ground gyuto from Aldo's 1/8" 1095. My first attempt warped pretty badly, and the other two cracked in water in a magnificent sori of destruction.

I finally smartened up and have two gallons of a 9% brine solution dissolving, to which I'll add some dish soap. I triple normalized with a torch last night, stepping from non-magnetic to darker non-magnetic temps. I used a torch because I'm becoming wary of my diy kiln, which may have caused some minor decarb last time.


You can read to hear your thoughts on an interrupted edge quench for this knife, 2 seconds in and 2 out. I'm trying to be extra cautious this time because I think my other mistakes could have been preventable. I also sanded to an even 320 grit, and slightly radiused all sharp corners. Also FWIW, my other attempts were with a clay coating.
Click to expand...

Have you tried a 2 second quench in water with a rapid quench in a fast oil? I read something along those lines in Keven Cashen's website.
 
I forgot to mention that in the OP. I'm trying to weigh the pros and cons of interrupted brine quench and switching from brine to veg oil. It seems like the latter would be the safest, so I might give that a shot.
 
Once you get the temperature of the blade below the pearlite nose you have (relative to avoiding the pearlite nose) a lot of time to get to 400 F. You might be able to let the blade air cool after the interrupted quench. Let us know how it turns out.
 
Heated up to 1500F, pulled out and edge quenched for 2 seconds in brine with some dish soap, and then moved into 120F veggie oil.
I thought the worst was over, but then I heard two little tinks{/I] in the oil. The bad news is I used up all my 1095, but the good news is I'm going to head over to Aldo's to get some 1084 and get this damn thing made.
 
Just want to share my newbly tinkered experiences.. What worked for me maybe just lucks, so ymmv ;)

If you want to try again with your broken 1095 as test. Do a full dip into brine (no soap, brine is plenty fast) for 0.5 second to lower the blade temperature about above the pearlite nose (between 1300-1200F), then pull spine out of brine to edge quench for 1.5 second then interrupt into room temp canola oil.

Good to avoid transformation phase line where dimensional differences too great which could tear edge apart. Just keep in mind that sharp quench-line and harmon look nice but probably won't be good (as intentional defect) when having a martensite next to pearlite section without a band of blending/mixing region.

I too, got a ping when did a (non-interrupt) edge quench into super-quenchant (brine+soap+surfactant). Now, whenever I want a safe quench line for some low Mn steel without using clay, I do what outlined above.

James Hall said:
Heated up to 1500F, pulled out and edge quenched for 2 seconds in brine with some dish soap, and then moved into 120F veggie oil.
I thought the worst was over, but then I heard two little tinks{/I] in the oil. The bad news is I used up all my 1095, but the good news is I'm going to head over to Aldo's to get some 1084 and get this damn thing made.
Click to expand...
 
I went back to the OP, and I realized this is a kitchen knife. With such a thin blade, warm canola oil is probably plenty fast, but as Bluntcut stated, a quick dunk would probably get you past the pearlite nose. Using the torch to normalize may have been an issue as well, leaving you with inconsistent grain structures throughout the steel. I would suggest going back to the kiln for normalizing. I have used water based brazing flux (used in fillet brazing bicycle frames) to prevent decarb during normalizing. Make sure you soak it off before the final heat treat as it will insulate the blade.
 
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