Thread: Interupted quench??

http://www.cashenblades.com/info/steel/1084.html

Deckard, to answer your original question, the only place in the UK that comes up on a search and gives direct information/specs about their oils is Aztec Oils. Their numbering system does not readily translate to US equivalents. There is a website for Houghton UK with a phone number. I also suspect both will want to sell 55 gallon drums and not in small liter quantities.

Canola oil and peanut oil will work just fine. The peanut oil will take a higher temperature if that's what you need.

Houghton, at least in the USA, has a reputation for being very accommodating to knifemakers and is willing to sell small quantities. I believe their Houghton "Quench K" is the fast oil that you would want for 1085, 1095, etc. You can download info on it from the bottom of this page. Contact Houghton's UK rep and see what they can do for you.

Thanks fellas for what is a good selection of varied approaches to this.
I like Mike Blues pragmatic approach and think I need to make more blades and try a bunch of stuff, including using brine to quench. Not sure such a thin section as a razor would necessarily need to be interupted during quenching in veg oil??
I'm always curious to how this is done rather than why, watching Kevin I estimate the blade is quenched for about 4 - 5 seconds? Chris thanks again for technical info, though I can never understand the time scale on those charts at risk of sounding dumb!

Time scale is measured in seconds. 10 to the second power is 100 seconds etc. On the 1080 TTT diagram that Chris provided, for example, the lefthand dark line represents the change from austenite to martensite, pretty much drops off the bottom of the chart right about 100 seconds, with a theoretical increase in hardness somewhere above 57 (right hand margin). According to this curve, 1080 should be quenched to below 1000 F within 1 second. Once you get past "the nose of the curve", as it's called, then you have up to about a minute and a half to get the blade straight or fiddle with it before all the martensite begins to interfere with this plastic moment in the blade's life. This is essentially the interrupted quench area under the curve that Kevin is playing with. This diagram shows both the M50 and M90 temperatures and it can be assumed safely that all conversion to martensite has occurred by 200 degrees F.

The science types didn't write this for normal people doing home built heat treatment. A little head scratching and calculation makes for easy recipes though.

Originally Posted by Deckard

...watching Kevin I estimate the blade is quenched for about 4 - 5 seconds?

Deckard, in case you decide to try the interrupted quench, the time until you can safely pull the blade out varies with the oil. Kevin was using Park's #50, so you might have to experiment a bit if you use a different oil. Too cool wouldn't be a big problem, but too hot and you could burn your hands. You are shooting for around 400 degrees. I always thought one of those hand held infrared temp meters might come in handy for checking the blade...

If you want to save a bit of money, bacon grease mixed with transmission fluid, beeswax, and saltpeter makes a nice quenchant for carbon steels. I used it for a long time, and since it's solid (although it can be heated for a liquid product) it's very clean, portable, and easy to handle. For small blades it can be used solid, but I would recommended heating it up for large blades.