Heat treating in a forge vs a kiln...what is your preference?

One of the best ways to do heat treatment:


Molten salt bath to normalizing, to harden, oil (or molten salt bath) to quench and molten salt bath to temper.

I believe the sword used (and made by him, in 1075 steel) by the gentleman who won Forged in Fire Knife or Death season 1 was also heat treated using molten salt bath, and that sword performed flawlessly. If I was in the market for a sword, I wanted no less than that.
 
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You know ... listening to this from the outside, so to speak, i keep waiting for someone to say “you can take my forge out of my cold, dead, fingers.... :-)
 
I enjoy HT'ing in the forge. It is satisfying to forge a blade and quench it and be ready to temper.

It is not nearly as easy to get a good HT as an oven. In my humble opinion, HT'ing in a forge by "eye" is a skill set unto itself, and one best developed along side an oven.
 
tkroenlein said:
I enjoy HT'ing in the forge. It is satisfying to forge a blade and quench it and be ready to temper.

It is not nearly as easy to get a good HT as an oven. In my humble opinion, HT'ing in a forge by "eye" is a skill set unto itself, and one best developed along side an oven.
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So is there any way around this? (I'm asking everyone) I don't have an oven, nor can I afford one any time soon. That coupled with the fact that I use 1080 and 1084 from NJSB which in previous threads was in question. If I can't be guaranteed the steel is 100%, what is the point of using an oven? Can someone who heat treats in a forge simply test the shit out of the knives they make beforehand to ensure that the customer is getting a good blade? If so, what tests would you recommend?
 
Sure there's a way around it. Practice. You can make great knives with just a forge. Lots have done it, and still do it. Practice consistency in your work habits, optimize your forge set up for temp control. You can test for hardness, even if you have to find local machine shops or whatever, and you can break coupons to see the grain. You can test edge deformation on your finished and sharpened knives.
 
R.C.Reichert said:
So is there any way around this? (I'm asking everyone) I don't have an oven, nor can I afford one any time soon. That coupled with the fact that I use 1080 and 1084 from NJSB which in previous threads was in question. If I can't be guaranteed the steel is 100%, what is the point of using an oven? Can someone who heat treats in a forge simply test the shit out of the knives they make beforehand to ensure that the customer is getting a good blade? If so, what tests would you recommend?
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Successful heat treat requires controlling as many variables as best we can. Using known steel with established heat treat protocols is the first part. Knowing your equipment is the second oart. Even with an oven, there is some variability from one to the next, so testing your results (such as Rc#’s) allows you to adjust to get the maximum.

if the steel is an unknown variability, then using a less reliable heat source cannot improve your results, it just adds a second uncertainty to the mix.

I have a reclaimed grader blade I have used for some hunters. I did no less than 20 coupons testing different heat treats to come up with a consistent, reliable approach, and get consistent Rc67 out of quench. 1470f for 10 min gets me that number over and over. Shorter soak, lower Rc#. Temp up or down by more than 20f, lower numbers.
 
What exactly are you guys referring to when you say "coupons"? I do edge quenches on all my blades, so I don't know how or if an RC tester would be able to test that since the hardness is on the bevel. I do the brass rod test and my edges flex and spring back nicely though.
 
R.C.Reichert said:
What exactly are you guys referring to when you say "coupons"? I do edge quenches on all my blades, so I don't know how or if an RC tester would be able to test that since the hardness is on the bevel. I do the brass rod test and my edges flex and spring back nicely though.
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coupons are small sample pieces of the steel. I use 1.5-2”x0.5” or so.
 
You're probably more experienced than me but to add on to what Willie was saying:

I've been striving to eliminate variables that are limiting my heat treat. I've got a homemade forge and a Atlas knife & tool Graham forge.

I personally eliminated all hypereuctoid steels from the lineup pretty early on and have settled almost exclusively on steels like 15n20 or 1075 that don't need a substantial soak at temperature. I wasted alot of otherwise good 1095 trying to get it right in my forge. The temperature window is just too small for me to catch and get right.

I've been messing with 80crv2 too but it's still hit or miss for me - verified by hardness testing files and some burrs that were impossible to get off the edge. Come to find out my eye fools me with 80crv2 - a blank I was sure was satisfactory was only about 55hrc out of quench. Y'know only about 10hrc lower than it should've been haha ... I could add a thermocouple, PID, all that... but I just don't see the point. Adding those things a heat treat oven does not make. lol

Eventually I'd like to have a heat treat oven alongside my forge(s). Forges for forging... heat treat oven for heat treating. So for now the super easy to heat treat steels are what I view as best. I'm still screwing with 80CRV2 and I have a bar of 8670 I want to try too... but even a small required soak makes it that much harder to get a good quench. A small muffle pipe has helped me with 80CRV2 but I swear 15N20 looks so much 'cooler' at temp than 80crv2 does... so I still mess up 80CRV2 alot and usually have to re-heat treat it again. And lord knows what that is doing to the integrity of the steel!

That's how I'm trying to approach this anyway:) just wanted to offer my perspective because we seem to be in similar boats
 
allenkey said:
You're probably more experienced than me but to add on to what Willie was saying:

I've been striving to eliminate variables that are limiting my heat treat. I've got a homemade forge and a Atlas knife & tool Graham forge.

I personally eliminated all hypereuctoid steels from the lineup pretty early on and have settled almost exclusively on steels like 15n20 or 1075 that don't need a substantial soak at temperature. I wasted alot of otherwise good 1095 trying to get it right in my forge. The temperature window is just too small for me to catch and get right.

I've been messing with 80crv2 too but it's still hit or miss for me - verified by hardness testing files and some burrs that were impossible to get off the edge. Come to find out my eye fools me with 80crv2 - a blank I was sure was satisfactory was only about 55hrc out of quench. Y'know only about 10hrc lower than it should've been haha ... I could add a thermocouple, PID, all that... but I just don't see the point. Adding those things a heat treat oven does not make. lol

Eventually I'd like to have a heat treat oven alongside my forge(s). Forges for forging... heat treat oven for heat treating. So for now the super easy to heat treat steels are what I view as best. I'm still screwing with 80CRV2 and I have a bar of 8670 I want to try too... but even a small required soak makes it that much harder to get a good quench. A small muffle pipe has helped me with 80CRV2 but I swear 15N20 looks so much 'cooler' at temp than 80crv2 does... so I still mess up 80CRV2 alot and usually have to re-heat treat it again. And lord knows what that is doing to the integrity of the steel!

That's how I'm trying to approach this anyway:) just wanted to offer my perspective because we seem to be in similar boats
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I stick with almost exclusively 1075-1084 steels for that reason. I also make knives that portray an older 18th century sorta time period, so these steel choices suit me just fine. I am not in the least interested in high-alloy or stainless steels.
 
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