AEB=L bad Heat Treatment?

Nick Riggi

Well-Known Member
I sent six knives out last week for heat treat to the same place I always have. The heat treater called me today to let me know that one of the six only hardened to 55 Rockwell ? All the steel came from the same place and that blank probably was cut from the same length as one of the others Has anyone had a similar issue and what could be the reason for this ??
 

KenH

Well-Known Member
I've tagged this thread hoping somebody with actual knowledge would respond. Personally, I wouldn't have a clue.
 

Nick Riggi

Well-Known Member
How much do you trust your heat treater?
Daniel, I trust them in so far as I have sent 7 batches (each usually with 5/6 blades) and of all of those- only 2 have Rockwell tested low (about 56)
All the rest come back at my requested RHC of 60/61 for AEB-L.
Honestly, even the 2 that came back low- skated a file and performed fairly well in some destructive testing. I was almost inclined to think it was just an anomaly in the Rockwell test itself.
I have 5 more getting sent out today to them. They test all the knives to be sure they are in the desired range- so we will see!
 

Self Made Knives

Well-Known Member
I do my own heat treat and I've never had an AEBL blade not harden fully. Something sounds off with the heat treater or you got some mis-labled steel.
 

Nick Riggi

Well-Known Member
Not really sure what happened with those 2 blades.
What RHC do do heat your AEBL to?
What process with temp and temper?
 

KenH

Well-Known Member
Since you are pretty sure the steel came from the same strip as some of the other blades that HT'd properly, I'd expect the problem to be an error in Rc testing. Just a VERY slight warp that might not be noticed and placed at test point could surely throw the test off a tad. Any idea how many places your HT'er tested the low Rc blade? The HT'er contacting you about the low Rc value before shipping back to you for discussion is a VERY good point in his favor for sure.

Nick, what part of the world are you in? If here in USA I'd be happy to retest those blades if you wish. Just two blades could be shipped 1st class for around $5 (each way) for 16 oz or less in a package/envelope. I doubt it's worth the $10 total shipping for testing, and if you're not in USA that's totally out of question. (one of the good reasons to have profile filled out).

Ken H>
 

Nick Riggi

Well-Known Member
Since you are pretty sure the steel came from the same strip as some of the other blades that HT'd properly, I'd expect the problem to be an error in Rc testing. Just a VERY slight warp that might not be noticed and placed at test point could surely throw the test off a tad. Any idea how many places your HT'er tested the low Rc blade? The HT'er contacting you about the low Rc value before shipping back to you for discussion is a VERY good point in his favor for sure.

Nick, what part of the world are you in? If here in USA I'd be happy to retest those blades if you wish. Just two blades could be shipped 1st class for around $5 (each way) for 16 oz or less in a package/envelope. I doubt it's worth the $10 total shipping for testing, and if you're not in USA that's totally out of question. (one of the good reasons to have profile filled out).

Ken H>
Thanks for the offer. I am in NJ.
I have sent well over 40 knives to the same heat treater and only the two ever came back as not quite as hard. I guess one way to avoid this is to get my own heat treat oven which is on my list of purchases.
 

Andre Grobler

Well-Known Member
Thanks for the offer. I am in NJ.
I have sent well over 40 knives to the same heat treater and only the two ever came back as not quite as hard. I guess one way to avoid this is to get my own heat treat oven which is on my list of purchases.
Well sorry to say, but this is not a very good way to save time and improve your productivity... you need to dial in every oven, and retest frequently and learn the oven specific vagaries of measurement and heating... doing it well is a substantial rabbithole... if you want that rabbithole, nothing else is as rewarding, but i have to tell you mis measurement is most often the issue, prepping HRC samples is quite time consuming
 
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