Effects of double heat treat?

B

Biginboca

Gold Member
Joined
Mar 17, 1999
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1,690
I am hoping some of you with more heat treating experience can help me out with this.

I started work on a folder blade about 2 months ago. I had it pretty much ground in. Then I was distracted with other projects and when I came back to it last week I heat treated it. Now I am wondering... I think I might have heat treated it previously!

Will there be any ill effects here? Do I need to anneal the blade and start all over?

The steel is 154cm and I did a hardening at 1875 for 30 min, an air quench, and then a double temper at 375 for an hour each time.

But I now think I may have done all this twice...

What do you guys think?

Thanks for the help.
Al
 
Thanks George!

I am glad to hear that, I wasn't looking foward to annealing and doing this for a third time!

But after thinking about your answer I now have another question...
Let's say I am grinding a blade that has already been heat treated and I get the tip too hot (discolored). Can I just heat treat it again without annealing? From your previous answer I am thinking that this would be ok.

Thanks Again,
Al
 
Sorry,if you discolor the tip, you need to anneal and start over. Unless you can just grind off the discolored tip and reshape it a little.

As for the double heat treat, try it. You might like the results better with a double treatment or even a triple. It works well for steels i.e. 1095,5160,52100 etc.

Hope this helps!

------------------
Craig Blankenship
Blankenship Knives
http://www.blankenship-knives.com

[This message has been edited by knifemaker3 (edited 03-19-2000).]
 
I think craig is talking about double and triple temper..not heat treat..right? If i were you I would call Paul Bos and ask him about the 154/cause I think you need to consquentiously anneal the stuff before hardening...my thoughts.....not necessarily the facts.....and as for turning the tip blue, I am quite sure that steel changing color on the outside is not necessarily a sign that the steel got hot all the way to the center....have had this same effect many times with no ill effect.

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http://www.mayoknives.com


 
Ed Fowler has mentioned multiple hardenings followed up with multiple temperings in some of his articles, but I don't remember offhand if there were any benefits for multiple hardenings. The articles in question were reprinted in his book, "Knife Talk", though. Most of his work mentioned is with 52100, though, so it may not apply here.

------------------
Oz

Now, what other news did I have? Oh yes, IT'S A GIRL!!!
See her and my latest blades @
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