Should 15n20 from bandsaw blades be thermal cycled?

[coldsteelburns]

I have been curious about this for a while now.

Is it better to simply re-quench/harden 15n20 that came from bandsaw blades, or should they be thermal cycled before quenching?

I'm also wonder what you guys have experienced as being a good hardness/temper temperature for kitchen knives as well as for general utility knives, assuming full hardness has been achieved.

I still have yet to use any 15n20 as a mono steel blade of for the cutting edge in anything laminated and I'm about to take advantage of the thinness and width of the steel by making a kitchen knife to start with.

FWIW, I am using the 15n20 'sheets' that I got from JT here on the forum.

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Also, I guess this falls into the same question as above but more in general. Let's say you heat treat a blade and everything about the heat treat and grain structure is sound, except when tempering you accidentally over-temper it and so it needs to be re-hardened. Does the blade (steel) really need to be thermal cycled again before re-quenching?

I feel like I learned the answer to this some years ago but since I haven't had to apply it at all, it's been pretty much been lost from my memory lol. I believe I remember some makers saying that it needs to be completely re-done, as in re-normalized, thermal cycled, and quenched.


Thanks in advance.

~Paul
My YT Channel
Lsubslimed
... (It's been a few years since my last upload)

 

[Willie71]

I just run them through a 1200f 2h subcritical anneal if I need to drill them. Otherwise, profile and heat treat.

Re:2nd question: just re heat treat and temper at the correct temperature. For kitchen knives, 300-325f seems to work well for me. You can use 275 for a really hard blade. I get 1-2 Rc points higher than the AKS chart, using DT-48 as a quenchant and 1465f austenitize temp. Don't austenitize above 1475. You will lose hardness that way. 1460-1475f seems to be the sweet spot in my shop.

(This is all for 15n20)

 

[JTknives]

Sorry I have not responded yet to your email. I will try and do it tonight.

 

[coldsteelburns]

Thanks Warren, I appreciate it.

Thanks JT (can't remember your name for some reason), that sounds great!

Need to apologize. I honestly just wasn't sure how often you check your email so that's why I went ahead an asked here. I go a number of days, even a week without checking mine every now and then, especially when I'm not expecting anything.

~Paul
My YT Channel
Lsubslimed
... (It's been a few years since my last upload)

 

[Darrin Sanders]

I do a full anneal, drill, saw, grind, etc., normalize, thermal cycle, then re-harden.