Heat Treating and Metallurgy Discussion of heat treatment and metallurgy in knife making. |
09-28-2017, 11:28 AM
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Steel Addict
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Join Date: Dec 2012
Location: San Antonio Texas
Posts: 163
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Right....don't quench in oil with the foil still on. I don't think the oil would make good contact with the blade with the foil on it, especially if there are air pockets in the foil (shouldn't be I don't think....but not a good idea regardless).
There could be a number of issues why a pre ground blade of AEBL didn't harden. And this came up on another forum just the other day (thought you were the same guy, JDALE, but I don't think you were after checking). This is just simple physics and is just simply NOT true. (that pre ground blades of SS will not harden at the edge). What makes SS so different than carbon steel? As a matter of fact, SS has pearlite nose of MINUTES, compared to some steels that have a pearlite nose of ONE SECOND, like W2 and 1095. People have been successfully hardening SS and carbon steel blades with pre ground bevels for a LONG time. I have done it since I started, when I only had files and basically HAD to have my bevels ground before hand. Carbon and stainless. Like I said, I send all of my high alloy tool and stainless steels to Peter's with the bevels pre ground, and they came back at the HRC i requested every single time. Only 2 aebl blades out of many were only profiled. The rest were beveled. And again, I was told Peter's doesn't use plates....just a straight air cool. Regardless of the method of cooling, if the bevels are cut and the edge is thus thinner, it will cool faster than the spine will.
Your plates may not have made good contact with the bevels, which would be on you, NOT the fact that they were pre ground. And again, if an edge is THINNER than simply profiled (bevels already ground), then that edge is going to cool FASTER than the spine, plates or air.
Last edited by samuraistuart; 09-28-2017 at 11:30 AM.
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09-30-2017, 09:14 PM
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Guru
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Join Date: Jan 2016
Location: Now live in Las Cruces NM.
Posts: 1,345
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Thanks Stuart
I do wrap the foil on as tight as possible and always have considering its price and if I was doing a plate quench I always wrapped it skin tight as possible. The plates, being cooled would pull the heat out quickly and even the bevel got cooled quickly too. It is all air quench anyway and I never had an edge that wouldn't hold up. I have to give a lot of credit to Hinderliter HT in OKC for my D2 HT, they were my savior on that alloy. Also 440C, the first stainless I ever did and they did the HT leaving me a nice HRC 59-60 hardness which is about the most you can ask of that steel without some brittleness.
I did the plate quench for both D2 and 440C simply because I didn't want to expose the yellow hot metal to the air. I found out later that it doesn't foul the surface too bad if I was quick with the air blast. Hinderliter didn't inform me of that bit of information, thinking I had to have absolutely no surface oxidation. Blame my aerospace experience that sometimes manifests itself as perfectionist fussing.
I still think AEB-L is the easiest stainless to HT. The cryo is just dry ice, a decent 2200 degree oven and foil is all that is needed. Right behind it is 440C with or without cryo.
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10-01-2017, 04:33 AM
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Enthusiast
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Join Date: Aug 2017
Location: Springfield Mo
Posts: 95
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Thanks again for all the advice given! Im feeling a lot more confident on how i should approach the whole process, whenever i finally happen to get the new thermocouple for my kiln in.
I did stumble across one more question, though this one is more concerning tempering and grinding. Now, i usually use the color of the steel as an indicator of temperature to make sure that my tempering goes well, and that i dont screw anything up during finish grinding. Problem is, im used to carbon steels. So, question is, are the standard heat oxide colors applicable in the same way to stainless as they are carbon steels?
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10-02-2017, 11:33 AM
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Steel Addict
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Join Date: Dec 2012
Location: San Antonio Texas
Posts: 163
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I would never use the colors to determine my tempers. ever. There are so many variables that come into play that cause the colors to vary that it isn't a good idea at all to use them. Check your oven temp with a few different thermometers and or thermo couples.
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Tags
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1095, aeb-l, bee, blade, blades, brass, finish, folding knife, heat, heat treat, heat treating, heat treatment, knife, knives, metal, play, problem, profile, quenched, stainless, stainless steel, steel, tips, what kind, wrap |
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