Will near-boiling water mess up heat treatment?

lava_lamp

lava_lamp

Joined
Oct 5, 2006
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I have an "Instant Hot" water dispenser on my sink. It reaches a temperature nearing 200 degrees fahrenheit (right below boiling.) I routinely rinse my heat treated blades in that water after use.

Could that mess up the heat treatment?
 
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No - it won't have an effect on your blade. It may be hard on some types of wood handles though.
 
Or if your blades happen to be made of an alloy of metals that melts under 200F. Just don't burn yourself.
 
No. Tempering starts at 400-800 depending on the steel. I doubt you would have trouble even putting it in an autoclave.
 
You are using the best method I know of to clean your blades. I do this: - HOT water rinse, soap on a sponge scrub, HOT water rinse, towel dry. Steel is similar to our skin in this regard - the pores will open to be cleaned and the HOT water dries quicker than cold reducing the risk of rust.
 
Just out of interest, how cold does a blade need to get to mess up the heat treat or damage the blade?
 
Herr_Noobien said:
Just out of interest, how cold does a blade need to get to mess up the heat treat or damage the blade?
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Normal human endurance would likely be exceeded before the blade would be permanently damaged.

I have read where some tool steels can become excessively brittle in cold conditions, so you might be more likely to chip or break it -- but the brittleness is a temporary physical change and would be completely reversed once the knife returns to normal temps.
 
Cryo treatment is beneficial to a knife, it converts retained austenite (soft steel) into martensite (hard steel).
The only problem is that this freshly converted steel is un-tempered, so it would make the blade a little more brittle. That is, assuming the blade hasn't already had a cryo treatment. Usual temperatures for that kind of thing are between -80 and -120 Fahrenheit.
 
elkins45 said:
Normal human endurance would likely be exceeded before the blade would be permanently damaged.

I have read where some tool steels can become excessively brittle in cold conditions, so you might be more likely to chip or break it -- but the brittleness is a temporary physical change and would be completely reversed once the knife returns to normal temps.
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Yes, I seem to recall someone posting a while back who worked on oil rigs (??) or something similar in northern Alaska. He mentioned that he needed a larger knife with a more flexible steel because otherwise they would have breakage problems with the tips in the below-zero temperatures. Sorry this is anecdotal, but the search function didn't turn up the post I was looking for.

- Mark
 
Sudden cooling can cause brittle fracture, but it is very rare in knives. If you take your knife out of your nice warm pocket to make a cut in 40 below temperatures, be very careful with it. Dropping the temperature 100 degrees in a few seconds can cause it to break if it is stressed at the same time. Look up what happened to some of the Liberty ships in WWII.
 
StretchNM said:
You are using the best method I know of to clean your blades. I do this: - HOT water rinse, soap on a sponge scrub, HOT water rinse, towel dry. Steel is similar to our skin in this regard - the pores will open to be cleaned and the HOT water dries quicker than cold reducing the risk of rust.
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Exactly! +1:thumbup::)
 
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