How to determine if heat treat worked and truly hardened?

M

Matisw

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Oct 17, 2018
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Bought some 5160 steel on ebay, shaped my blade, etc, and now I am going to heat treat.

In the meantime, I looked online and saw that my seller has gotten some very bad reviews lately; specifically, buyers saying steel they bought from him wasn't what seller represented, and that the steel they received won't harden.

So, how can I determine if after heat treating, (heating up to non-magnetic, quenching, then baking at 425 degrees for 2 hours, etc) actually was successful and that the blade was truly hardened?

Thanks.
 
I have no experience with 5160. But when you quenched it, just scrape it with a file. If it skates over and doesnot cut into the steel. Its hardend. Do ths carefull. At this stage the steel is brittle.
 
keep a piece of the metal that you cut off when doing the profile. after heat treating your blade compare it with a file against the piece you cut off before heat treat. there should be a noticeable difference. also, the critical temp is about 100 degrees past non magnetic. bring your blade to non magnetic, then bring it one shade brighter red before quenching.
 
john april said:
keep a piece of the metal that you cut off when doing the profile. after heat treating your blade compare it with a file against the piece you cut off before heat treat. there should be a noticeable difference. also, the critical temp is about 100 degrees past non magnetic. bring your blade to non magnetic, then bring it one shade brighter red before quenching.
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I completely agree with John. Feeling a file "skate" isn't intuitive the first few times. Keep a piece of scrap to compare against.
 
thanks, will try, I THINK that I saved a scrap of the metal, good thing to know for next time.
 
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A blade hardened with a 400 degree temper may be able to be cut by a file but it wouldn't be easy and you would feel like its dulling the file. If you have leftovers try heating a small piece and quenching in water. The file should skate and not cut at all. The piece should be brittle and break rather than bend if hit in a vise.
 
A file may still bite on the thin decarburized layer at the surface after heat treat. Some people like to clean it up a bit first then try the file. I just run the file a few times along the edge until it (usually) hits the hardened steel.
 
You could do a subcritical anneal [ 1200 F x2 hours. Much easier.
 
mete???
I think you are answering a different thread. This is about how to tell if the blade hardened after HT .... without test equipment.
 
Where are you located? Any machine shops around? I used to carry mine by a local shop and they’d check a couple from each batch.
 
I live in New York, near White Plans. Anyhoo, I heat treated and it doesn't appear to be hardened, it is easily scratched deeply, there seems to be no difference between the hardness of the handle which was not treated and the blade, and I can file the edge very easily
 
Good places to buy steel
AKS - Alpha knife supply
NJSB - New Jersey steel baron-"Aldo"
Pops knife supply
 
Matisw said:
I live in New York, near White Plans. Anyhoo, I heat treated and it doesn't appear to be hardened, it is easily scratched deeply, there seems to be no difference between the hardness of the handle which was not treated and the blade, and I can file the edge very easily
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Set up your account to private message. I am in Orange county NY.
Your less than an hour from Aldo's shop. Great place to visit and get some steel no shipping!!

Jim
 
Thanks Britt and Jim, where is that setting for personal message??? Is it only for paid members? Can't find it.
 
It may be? The cheapest membership might cover it and for a few $ would be well worth it. Someone who knows should respond soon.
 
thanks, ok, NJSB - New Jersey steel baron-"Aldo" looks like only a web presence, will check it out, and let you know, you can imagine the frustration of working on a blade and doing everything right and it turns out the steel is shooty. Excuse my french.
BUY FROM A RELIABLE DEALER! Glad I learned this lesson on my very first knife.
 
The steel is more than likely OK steel, but unless you know the internal condition and can do a proper HT, it may not harden properly.
5160 requires a soak for about 5 minutes at 1525F. Getting it red and non-magnetic isn't enough to harden it right.

Also, file the edge vigorously with your file. It may have a deep layer of de-carb. Just a light stroke or two may not bite deep enough.

Finally - Buying from AKS, USA Knifemakers, Aldo, etc. will assure good steel and proper condition along with verified HT specs.
 
"Only a web presence"? Not hardly, bud. Ha! I may have to use that one the next time I talk to him. "Hey Aldo, you do realize you're only a web presence, right?!"
 
I'm just over the bridge in Rockland. If you were going to be in the area I could give you a piece of 1084 or 15n20 to play with. Aldo is in north Jersey and there are a few other makers in the area I think though I haven't met them all.
 
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