04-02-2018, 01:33 PM
Mr. Jan, that is a very interesting attachment! I haven't heard of quenching under vacuum pressure, but it makes perfect sense. Engineered quench oils are designed with additives to eliminate the vapor jacket, because that is critical to cooling the steel. That's why I use quench oil designed for this purpose. I have no idea how to go about quenching a blade in a vacuum. I've never heard of it, but that would be the ultimate way to defeat the vapor jacket!
I agree that faster quenching can result in warped blades, but there are ways to get around it. I rely on multiple thermal cycles, and straightening the blade after each cycle. After the grain refinement heat cycles, the blades stay straight 90% of the time. I would do grain refining cycles no matter what, so a little extra blade straightening during that time is no inconvenience.
My final proof of heat treat quantification is testing to destruction, which is something I do constantly. My normal hunting/survival blade will withstand elastictic deformation flexing back and forth to 30°. At 45°, I get about 5° plastic deformation. At 90° flex, I get about 45° plastic deformation.
Some steels can be purchased ready for hardening. I know Aldo sells 1084, but hypereutectoid bar stock like 52100 is most often heavily spheroidized to make it easier to work. It takes a very significant heat cycle just to dissolve and distribute the carbon before you can work at refining the grain.
Temperature is one aspect of heat treating, but time is just as important to all heat treating cycles. Too hot for too long causes grain growth, but steel has to be a certain temperature for a certain time to fully dissolve the carbon and other alloys. The higher carbon and alloys, the higher the temp and/or longer the soak.
Mr. Scott, I will quote your mostly highlighted statement;
(Quote) (sic)how much steel will flex depends on geometry not heat treat. here is a good reference http://www.hypefreeblades.com/forum/view...?f=3&t=244
a quote from the article: This physical fact also rules bending tests and test alike when bending is involved. And as Kevin mentioned before, it is material related and doesn't get changed by whatever HT on does on the blade. (Unquote)
I think you're taking this out of context or something, because to take this literally is ridiculous. Heat treat makes no difference on a blade's ability to flex? So identical blades, one lightly tempered (still very hard) and one heavily tempered (much tougher) will flex equally? Not to mention Mr. Jan's testament related to the benefits of heat treating to refine the grain. Not to mention the most critical step in my heat treat regimen- drawing the spine....
I don't rely on normal tempering to achieve my goals. I temper the blade at 365°F for two hours, twice. In reality, only the edge of the blade remains HRC 62. I figured a way to draw the rest of the blade down to about HRC 50, which leaves me with perfect martensitic spring steel. The performance of my knives has been documented in YouTube videos for many years. Of course I welcome side by side comparison of every aspect.
I agree that faster quenching can result in warped blades, but there are ways to get around it. I rely on multiple thermal cycles, and straightening the blade after each cycle. After the grain refinement heat cycles, the blades stay straight 90% of the time. I would do grain refining cycles no matter what, so a little extra blade straightening during that time is no inconvenience.
My final proof of heat treat quantification is testing to destruction, which is something I do constantly. My normal hunting/survival blade will withstand elastictic deformation flexing back and forth to 30°. At 45°, I get about 5° plastic deformation. At 90° flex, I get about 45° plastic deformation.
Some steels can be purchased ready for hardening. I know Aldo sells 1084, but hypereutectoid bar stock like 52100 is most often heavily spheroidized to make it easier to work. It takes a very significant heat cycle just to dissolve and distribute the carbon before you can work at refining the grain.
Temperature is one aspect of heat treating, but time is just as important to all heat treating cycles. Too hot for too long causes grain growth, but steel has to be a certain temperature for a certain time to fully dissolve the carbon and other alloys. The higher carbon and alloys, the higher the temp and/or longer the soak.
Mr. Scott, I will quote your mostly highlighted statement;
(Quote) (sic)how much steel will flex depends on geometry not heat treat. here is a good reference http://www.hypefreeblades.com/forum/view...?f=3&t=244
a quote from the article: This physical fact also rules bending tests and test alike when bending is involved. And as Kevin mentioned before, it is material related and doesn't get changed by whatever HT on does on the blade. (Unquote)
I think you're taking this out of context or something, because to take this literally is ridiculous. Heat treat makes no difference on a blade's ability to flex? So identical blades, one lightly tempered (still very hard) and one heavily tempered (much tougher) will flex equally? Not to mention Mr. Jan's testament related to the benefits of heat treating to refine the grain. Not to mention the most critical step in my heat treat regimen- drawing the spine....
I don't rely on normal tempering to achieve my goals. I temper the blade at 365°F for two hours, twice. In reality, only the edge of the blade remains HRC 62. I figured a way to draw the rest of the blade down to about HRC 50, which leaves me with perfect martensitic spring steel. The performance of my knives has been documented in YouTube videos for many years. Of course I welcome side by side comparison of every aspect.