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Author Topic: beginning tests to work up a base heat treat with 440c  (Read 2531 times)
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Joe Calton
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« on: July 31, 2015, 09:46:07 AM »

https://youtu.be/pu66Bca_4yw

https://youtu.be/Zs_-pDXR9XU

https://youtu.be/uPHFIVGmkRE

It looks like I am getting pretty close to a base heat treat! these knives are starting to change the way that I look at stainless knives. they are cutting and flexing like no other stainless knife that I have ever used, and I think they still have a long ways to go.

today I am retempering the one 15 minute blade I have left at 15 degrees hotter, and will retest it for cut and edge deformation. also just got 6 more testers ready for heat treat and testing. going to do 2 at 15 minutes, 2 at 10 minutes, as the 15 minute one had noticeably finer grain than the 20 minute one, and during the edge deformation test, you will notice that the chip from the 15 minute one hung on to the rest of the edge, while the 20 minute one chipped out cleanly, then 2 at a heat treat that was suggested by a friend, which involves the multiple quench, but in a way that I haven't tried before:

heat at the upper range of heat suggested by the manufacturer, then quench, then temper very hot.

then heat to the lower temp and time, quench, and temper as normal, or below normal and work up.

I still need to test to see if tempering the spines/tangs with a torch will produce a good differentially tempered blade, test for stain resistance in salt water {already did plain water, and it did not discolor or rust when placed in a pan of water for 24 hours}.

I think in a week or so, I will have a good base heat treat, and then will start playing with more multiple quenching, heat cycles, possible cold treatments, different thickness stock, different grinds to see what the steel will do at different grind thicknesses, ect..... but im pretty happy so far and im only 9 testers in! another 10-20 should get me about where Id like to be I think to start with, and then its just a matter of time and chasing down variables!    

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John Silveira
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« Reply #1 on: July 31, 2015, 11:38:28 AM »

great testing !

i've not ventured at all toward Stainless for the same reasons you mentioned. Good seeing your results and info.

thnx for posting
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Ed Fowler
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« Reply #2 on: August 01, 2015, 03:17:08 PM »

Good work Joe! I would like to see you use a torque wrench to gain a little more information from the blades you test.

Watching those blades snap reminds me why I started forging blades, a replay of my worst nightmare.

Both Gill Hibben and Bob Loveless started out forging 440C because they could not get the size they wanted so forged round stock. Many claim that you gain nothing from forging stainless, but Joe Szilaski feels he can gain in performance.

I do remember that the stainless bearing I forged was very tough, could do the 90 degree flex. I did not have Rex to analyze the steel for me so am not sure it was 440 C even though the manufacturer said it was, sometimes stuff gets mixed up.

Thanks for sharing!!
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Daniel Rohde (D-Vision)
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« Reply #3 on: August 01, 2015, 07:00:33 PM »

Sorry I haven't repied earlier,(been on a trip)

First, I just love your videos! You always have good things to say!


I had on question/concern, do you cut the blade cross sectional to the steel bar stock? Wouldn't you want tr cut the blade as to have the "grain" following with the design?

Losts tonstlltest and try but I have allot of confidence that you figure it out. I still think you should try a full harden with a spine draw, and also try hearing only the edge and full quenching.

Keep making the videos!! They are a big help to me....at the very least.
DR....
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ChrisAnders
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« Reply #4 on: August 09, 2015, 07:24:02 PM »

Hey Joe.  I didn't see any details on how you did the water tests.  Did you fully submerge the blades or leave part in and part out of the water?
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Joe Calton
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« Reply #5 on: August 16, 2015, 05:38:31 PM »

Daniel, I do cut the blades "with the grain" on the video where one sheet of steel was shorter than the other, I cut off enough lenth to get the lenth of the knives, and then cut them out lengthwise from the cut off section.

Chris, I have not tried quenching the 440c in water, I did try about 20 1095 blades in water, but did not come up with anything that I was happy with yet, I do have some ideas, so maybe when I get a slow week ill try another 20 blades and see what I find.
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ChrisAnders
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« Reply #6 on: August 20, 2015, 11:32:36 AM »

Sorry Joe.  I should have been more clear.  I meant on the corrosion soak in water.  A blade that is partly in and partly out of the water can show corrosion near the water line, even when it doesn't show anywhere else.
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Joe Calton
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« Reply #7 on: August 20, 2015, 09:49:14 PM »

chris,  oh, gotcha, I took the blades, and a metal cookie sheet that I keep in the shop, placed the blades in the cookie sheet, and poured water into the sheet until the blades were just barely covered with water. here in Cheyenne, it is very dry. so I figured that the water would evaporate pretty quickly and it did, by the next day the water was gone, but there wasn't any sign of rust or discoloration on any of the blades.

but, I did make a small paring knife, didn't even put a handle on it and put it in the kitchen for a longer term corrosion and use test, and I noticed this afternoon, that there is some discoloration on it. not very much, and just on a part of the blade, behind the edge. which tells me that something that I cut with it was acidic enough to discolor it. as if it was just water, then the whole blade would be discolored. im not sure what it was that did it, but now that I know that something did it, ill keep better track and hopefully figure it out. it may also have to do with the fact that I left it at a 220 grit belt finish.
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