Heat Treating

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polojeff

Joined
Feb 6, 2010
Messages
36
Hey guys,

I'm almost done with my first knife, but I haven't figured out a heat treating solution yet. I don't have a kiln or anything that gets hot enough. How and where should I send the knife to be HT'd?

Thanks and my apologies if this has already been covered,
Jeff
 
What kind of steel and what you are looking to do with it (plus a brief description and a pic) would really help out.
 
I don't have a camera right now, but it's 440A about 7-8 inches long. Its just a utility/general cutting stuff type of knife, mostly just a practice exercise in using the tools and methods.
 
hey i would like to know also where to send the stuff to get treated.
sorry not trying to highjack the thread but our questions are very similar.
i am in oklahoma if that makes a difference hopefully there is something close.

thanks

j
 
Texas Knifemakers Supply does a good job on air hardening steel,also Peters H/T in PA.
Stan
 
Jraney, heat treating ovens aren't hard to use other than realizing that you are dealing with temps between 1500-2000F. They do often require a 220V outlet, though you can get ovens that run on 110V. Other than that, they are pretty much plug and play with push-button controllers. The important thing to remember is that every steel type has it's specific heat treating "recipe", and that recipe needs to be known and followed to get a satisfactory result. That includes different hardening temps, different hold times, and different quench speeds. For quenching, you need to match the speed of quench to the steel. It could be fast which requires either a brine or formulated oil such as parks #50. For medium speed, you can use a formulated oil like AAA or something along the lines of canola oil. For air hardening steels, many makers use aluminum quench plates.

Do some research and get to know your steel. Heat treating is a critical part of making a great knife.

--Nathan
 
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so if i have 2 knives made of 440c they will have the same recipe right, but if i have 1 440c and 1 ats-34 they will be different times and temp and all that right? 1 more dumb question does every steel have to be quenched even if you use the oven to heat treat?
 
Heating is only one part of the equation. Heating to a specific critical temperature changes the internal structure of the steel into austenite. You must quench (cool past a critical temperature within a specific length of time) to transform that austenite into martensite without forming pearlite. So, yes, every steel requires a quench.

Now for stainless steels like the 440C you mentioned, the quench is much slower than, say, 1095. For 440C you will get hardening with air cooling, though may people use plates as a heat sink to more quickly cool the steel for maximum hardness. Keep in mind with stainless steels, you are heating to much higher temps (1900+) and holding for 30-45 minutes in many cases. As such, you need to protect the steel from decarb using stainless steel foil.

To answer your question, yes two blades of 440C will heat treat the same and ATS34 will be slightly different, though they're not too far off from each other. Check out the resources page on my website for some data sheets on many common bladesteels.

--Nathan
 
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