Heat Treatment Question

[Spade]

At what temperature will higher quality steels begin to loose their tempers? Knife manufacturers will advise against using a grinder to sharpen a blade, yet blades are often polished on buffers that also can cause heat. I have read elsewhere in the forums where high quality knives were held beneath hair dryers to loosen the lock-tite on screws. I understand that flames are out, but where is the border. I would be specifically interested in knowing this for 154-CM and regular carbon steel.

 

[mikeS]

If I temper (carbon steel) blade at 450f.
In order to change the temper of the blade I have to exceed the 450f temperature of the orinal temper.

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Sola Fide

 

[lively]

I haven't noticed any difference to the hardened edge until you get to around 350degF. There are things occurring in the steel though. Stress relief I think starts at around 200degF in high carbon steel. As far as tempering goes where you are actually changing the RC hardness values, it seems to me to start around 350. Like Mike was saying though, you have to exceede the temper that already there before you would lose hardness. Grinding can create more heat than you might think. Especially in one small thin spot like on an edge.

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http://www.livelyknives.com

 

[Spade]

Thanks guys. Is the hair dryer out? I have no idea how hot these things get. Also, is the treatment on production knives typically different than customs?

 

[mikeS]

I don't think a hair dryer would be too hot I'm guessing it is not over 200f.

Production knives use the same basic principal.

search the archives here for info and links to heat treat.

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Sola Fide

 

[Kevin Wilkins]

You won't hurt the temper of a knife blade with a hair dryer - unless you've you've got a hair dryer for Marge Simpson Hair.

If the steel starts to change color like turning brown or blueish, then you damaged the temper in those spots.

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http://www.wilkins-knives.com
http://www.wilkins.de

 

[Spade]

Again, thanks for the help.

The only experience I have with this sort of thing occurred when I crudely tempered steel with a torch in shop class unbeknownst to my teahcer.

I would bet that I am the first person you have met that got an F in shop!

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"Tis better to have it and not need it, than need it and not have it."

Capt. Woodrow Call
(I think).

 

[Spade]

Ich haetta wissen sollen dass hilfe aus Deutschland kommen wird!

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"Tis better to have it and not need it, than need it and not have it."

Capt. Woodrow Call
(I think).